Solid Fuel Use and Incident COPD in Chinese Adults: Findings from the China Kadoorie Biobank

Residential energy transition and chronic respiratory diseases

Obtaining clean energy is of prime importance for planetary health and sustainable development. We aimed to assess the association between residential energy transition and the risk of chronic respiratory diseases. Using data from the Global Health Observatory and Global Burden of Diseases, Injuries, and Risk Factors Study, we delineated the spatial distribution and temporal trends of the population using clean fuels for cooking at a global scale. In the China Health and Retirement Longitudinal Study, we performed rigorous and well-structured multistage analyses incorporating both cross-sectional and prospective data analyses to examine the associations between solid fuel use, residential energy transition, duration of solid fuel use, and the risk of chronic respiratory diseases. Despite great progress, huge disparities in access to clean energy persist globally. Residential energy transition was associated with a lower risk of chronic respiratory diseases. In the period of 2011-2013, compared with persistent solid fuel users, both participants who switched from solid to clean fuels (adjusted risk ratio [RR] 0.78, 95% confidence interval [CI] 0.62-0.98) and persistent clean fuel users (adjusted RR 0.71, 95% CI 0.57-0.89) had significantly lower risk of chronic respiratory diseases (p < 0.001 for trend). Consistent associations were observed in the period of 2011-2015 and 2011-2018. Household energy transition from solid to clean fuels could reduce the risk of chronic respiratory diseases. This is a valuable lesson for policy-makers and the general public to accelerate energy switching to alleviate the burden of chronic respiratory diseases and achieve health benefits, particularly in low- and middle-income countries.

Association between cooking fuel exposure and respiratory health: Longitudinal evidence from the China Health and Retirement Longitudinal Study (CHARLS)

The epidemiological evidences for the association between cooking fuel exposure and respiratory health were inconsistent, and repeated-measures prospective evaluation of cooking fuel exposure was still lacking. We assessed the longitudinal association of chronic lung disease (CLD) and lung function with cooking fuel types among Chinese adults aged ≥ 40 years. In this prospective, nationwide representative cohort of the China Health and Retirement Longitudinal Study from 2011 to 2018, 9004 participants from 28 provinces in China were included. CLD was identified based on self-reported physician diagnosis in 2018. Lung function was assessed by peak expiratory flow (PEF) in 2011, 2013 and 2015. Multivariable logistic and linear mixed-effects repeated-measures models were conducted to measure the associations of CLD and PEF with cooking fuel types. Three-level mixed-effects model was performed as sensitivity analysis. Among the participants, 3508 and 3548 participants used persistent solid and clean cooking fuels throughout the survey, and 1948 participants who used solid cooking fuels at baseline switched to clean cooking fuels. Use of persistent clean cooking fuels (adjusted odds ratio [aOR] = 0.73, 95 % confidence interval [CI]: 0.61, 0.88) and switch of solid fuels to clean fuels (aOR = 0.81, 95 % CI: 0.67, 0.98) were associated with lower risk of CLD. The use of clean cooking fuels throughout the survey and switch of solid fuels to clean fuels in 2013 were also significantly associated with higher PEF level. Similar results were observed in stratified analyses and different statistical models. The evidence from CHARLS cohort suggested that reducing solid cooking fuel exposure was associated with lower risk of CLD and better lung function. Given the recent evidence, improving household air quality will reduce the burden of chronic lung diseases.

The relationship between cooking fuel use and sex hormone levels: A cross-sectional study and Mendelian randomization study

PURPOSE

The aim of this study was to investigate the effect of solid fuel use on serum sex hormone levels. Furthermore, the effects of improved kitchen ventilation and duration of cooking time on the relationship between solid fuel use and serum sex hormone levels will be further explored.

METHODS

In this cross-sectional study, 5386 individuals were recruited. Gender and menopausal status modified associations between solid fuel type and serum sex hormone levels was investigated through generalized linear models and further analyzed by improving kitchen ventilation and length of cooking time on the relationship between solid fuel use and serum sex hormone levels. To identify the causal association, mendelian randomization of two-sample was performed.

RESULTS

In observational analyses, for ln-17-hydroxyprogesterone, ln-testosterone, and ln-androstenedione among premenopausal women, the estimated β and 95 % CI of sex hormone levels for the effect of solid fuel users was -0.337 (-0.657, -0.017), -0.233 (-0.47, 0.005), and - 0.240 (-0.452, -0.028) respectively, and - 0.150 (-0.296, -0.004) in ln-progesterone among postmenopausal women. It was found that combining solid fuels with long cooking periods or no ventilation more effectively reduced testosterone and androstenedione in premenopausal women. We further found the adverse effects of using solid fuel on progesterone, testosterone, and androstenedione levels were enhanced with the increases of PM1, PM2.5, PM10, and NO2. Corresponding genetic, the causal risk effect of solid fuel were - 0.056 (-0.513, 0.4) and 0.026 (-3.495, 3.547) for testosterone levels and sex hormone binding globulin, respectively.

CONCLUSION

Using gas or solid fuel was negatively related to sex hormone levels. A combination of using solid fuels, cooking for a long time, or cooking without ventilation had a stronger effect on sex hormone levels. However, genetic evidence did not support causality for the associations. WHAT IS ALREADY KNOWN ON THIS TOPIC?: The mechanisms underlying these associations household air pollution (HAP) from incomplete combustion of such fuels and occurrence of chronic diseases remained obscure. Recent years, extensive evidences from animal as well as human researches have suggested that progestogen and androgen hormones are involved in the development of diabetes, hypertension, and cardiovascular disease, which indicated that changes in serum progestogen and androgen hormones levels might play a role in these pathological mechanisms. However, limited evidence exists examining the effect of HAP from solid fuel use on serum sex hormone levels.

An investigation of the risk factors of chronic obstructive pulmonary disease in natural population-based cohorts in China - a nested case-control study

Background

Chronic obstructive pulmonary disease (COPD) has become one of the most significant chronic diseases in China. According to conventional wisdom, smoking is the pathogenic factor. However, current research indicates that the pathophysiology of COPD may be associated with prior respiratory system events (e.g., childhood hospitalization for pneumonia, chronic bronchitis) and environmental exposure (e.g., dust from workplace, indoor combustion particles). Dyspnea, persistent wheezing, and other respiratory symptoms further point to the need for pulmonary function tests in this population. Reducing the burden of chronic diseases in China requires a thorough understanding of the various factors that influence the occurrence of COPD.

Methods

Using a cohort from the natural population, this study used nested case-control analysis. We carried out a number of researches, including questionnaire surveys and pulmonary function testing, in the Northwest and Southeast cohorts of China between 2014 and 2021. After removing any variations in the baseline data between patients and control subjects using propensity score matching analysis, the risk factors were examined using univariate or multivariate regression.

Result

It was discovered that prior history of chronic bronchitis, long-term wheezing symptoms, and environmental exposure-including smoking and biofuel combustion-were risk factors for COPD. Dyspnea, symptoms of mobility limitation, organic matter, and a history of hospitalization for pneumonia at an early age were not significant in the clinical model but their incidence in COPD group is higher than that in healthy population.

Discussion

COPD screening effectiveness can be increased by looking for individuals with chronic respiratory symptoms. Smokers should give up as soon as they can, and families that have been exposed to biofuels for a long time should convert to clean energy or upgrade their ventilation. Individuals who have previously been diagnosed with emphysema and chronic bronchitis ought to be extra mindful of the prevention or advancement of COPD.

Household air pollution and risk of incident lung cancer in urban China: A prospective cohort study

Household air pollution (HAP) is associated with the development of lung cancer, yet few studies investigated the exposure patterns and joint associations with tobacco smoking. In our study, we included 224 189 urban participants from China Kadoorie Biobank (CKB), 3288 of which diagnosed with lung cancer during the follow-up. Exposure to four HAP sources (solid fuels for cooking/heating/stove and environmental tobacco smoke exposure) was assessed at baseline. Distinct HAP patterns and their associations with lung cancer were examined through latent class analysis (LCA) and multivariable Cox regression. A total of 76.1% of the participants reported regular cooking and 52.2% reported winter heating, of which 9% and 24.7% used solid fuels, respectively. Solid fuel heating increased lung cancer risk (Hazards ratio [HR]: 1.25, 95% confidence interval [CI]: 1.08-1.46). LCA identified three HAP patterns; the "clean fuel cooking and solid fuel heating" pattern significantly increased lung cancer risk (HR: 1.25, 95% CI: 1.10-1.41), compared to low HAP pattern. An additive interaction was observed between heavy smoking and "clean fuel cooking and solid fuel heating" (relative excess risk [RERI]: 1.32, 95% CI: 0.29-2.47, attributable proportion [AP]: 0.23, 95% CI: 0.06-0.36). Cases resulting from solid fuel account for ~4% of total cases (population attribute fraction [PAF]overall : 4.31%, 95% CI: 2.16%-6.47%, PAFever smokers : 4.38%, 95% CI: 1.54%-7.23%). Our results suggest that in urban China, solid fuel heating increased the risk of lung cancer, particularly among heavy smokers. The whole population could benefit from cleaner indoor air quality by reducing using solid fuels, especially smokers.

Association of cooking fuel use with risk of cancer and all-cause mortality among Chinese elderly people: a prospective cohort study

When cooking with biomass and fossil fuels, their incomplete burning can lead to air pollution, which can trigger pernicious effects on people's health, especially among the elderly, who are more vulnerable to toxic and harmful environmental damage. This study explored the association between different cooking fuel types and the risk of cancer and all-cause mortality among seniors constructing Cox regression models. Data were obtained by linking waves of 6, 7, and 8 of the Chinese Longitudinal Healthy Longevity Survey, which included a total of 7269 participants who were 65 years old and over. Cooking fuels were categorized as either biomass, fossil, or clean fuels. And the effects of switching cooking fuels on death risk were also investigated using Cox regression models. The results indicate that, compared with the users of clean fuels, individuals using biomass or fossil fuels were at a greater death risk for cancer [HR (95% CI): biomass, 1.13 (1.05-1.20); fossil, 1.16 (1.06-1.25)] and all causes [HR (95% CI): biomass, 1.29 (1.16-1.42); fossil, 1.32 (1.22-1.50)]. Furthermore, compared with sustained users of biomass fuels, individuals converting from biomass to clean fuels significantly reduced death risk for cancer [HR (95% CI): 0.81 (0.72-0.95)] and all causes [HR (95% CI): 0.76 (0.64-0.93)]. Similarly, all-cause death risk [HR (95% CI): 0.77 (0.62-0.93)] was noticeably reduced among these participants converting from fossil to clean fuels than persistent users of fossil fuels. Subgroup analyses revealed that males had a greater cancer and all-cause death risk when exposed to unclean fuels. These findings can inform the development of policies and the implementation of measures related to cooking fuel use to promote the health of older people and reduce the burden of disease on society.

Association between co-exposure of polycyclic aromatic hydrocarbons and chronic obstructive pulmonary disease among the US adults: results from the 2013-2016 National Health and Nutrition Examination Survey

Although existing epidemiological studies have reported the relationship between single polycyclic aromatic hydrocarbon (PAH) exposure and chronic obstructive pulmonary disease (COPD), little is known about the impact of PAH mixture exposure on COPD. Therefore, we aimed to evaluate the associations of single and mixed exposures to PAHs with COPD in US adults using data from NHANES 2013-2016 by fitting three statistical methods, including multiple logistic regression, Bayesian kernel machine regression (BKMR), and quantile-based g-computation (qgcomp) models. This study included 1836 participants aged 40 and older. Multiple logistic regression showed that 2-FLU, 1-PHE, 1-PYR, and 2&3-PHE increased the risk of COPD after adjusting for all covariates. The BKMR model identified positive trends between PAH mixture and the risk of COPD in all adults and males when all PAHs were at or above their 55th percentile compared to all PAHs at their 50th percentile. The qgcomp model suggested that PAH co-exposure increased the risk of COPD (OR:1.44, 95%CI:1.09, 1.90) when each quartile increased in PAH mixture concentration, with 2-FLU having the highest weight. The combined impact also be observed in men. In conclusion, PAHs co-exposure was associated with a higher risk of COPD, especially in males, with the positive impact of 2-FLU being the most important.

Transition of cooking fuel types and mortality risk in China, 1991-2015

BACKGROUND

The decision for household cooking fuel choice is a complex and multi-dimensional process. This study aims to: 1) examine the trend of cooking fuel types during past decades; and 2) examine the association between switching from polluting to clean fuels for cooking and mortality risk.

METHODS

This analysis included data on 39,359 participants from 9 waves of the China Health and Nutrition Survey (CHNS) (1991-2015). Participants with consistent polluting fuel use and with the polluting-to-clean transition were identified. Generalized estimating equations were used to examine the trend of clean fuel use from 1991 to 2015. Propensity score matching was used to address the data imbalance and confounding factors and Cox proportional hazards models were used to estimate the association.

RESULTS

We found an increasing trend of clean fuel use after adjusting for potential confounders in the full sample (OR = 56.89, 95 % CI: 48.17, 67.19), which appeared to be more pronounced for those in rural areas and with low socioeconomic status. Switching from polluting to clean fuels was associated with a 75 % lower risk of mortality (HR = 0.25, 95 % CI: 0.11, 0.54). These associations became more pronounced during the lag period from 9 to 15 years.

CONCLUSIONS

The transition from polluting to clean cooking fuels reduced excess deaths in China, particularly over a long period. Our findings support the increasing implementation of clean fuels and call for more efforts to improve its universal service, especially in rural and low socioeconomic status areas, to minimize health inequality.

Household Air Pollution and Adult Lung Function Change, Respiratory Disease, and Mortality across Eleven Low- and Middle-Income Countries from the PURE Study

BACKGROUND

Globally, household air pollution (HAP) is a major environmental hazard that affects respiratory health. However, few studies have examined associations between HAP and lung function decline and respiratory disease and mortality.

METHODS

We used data from the Prospective Urban and Rural Epidemiology study and examined adults residing in 240 rural communities in 11 low- and middle-income countries where HAP from cooking with solid fuels is common. Spirometry was conducted for 28,574 individuals at baseline and 12,489 individuals during follow-up (mean of 8 y between spirometry measures). In cross-sectional analyses, we compared lung function measurements [forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC), and FEV1/FVC ratio] in those who used solid fuels for cooking in comparison with clean fuels. Using repeated measurements of lung function, we examined the percent change in lung function measures per year, comparing individuals by baseline fuel type and individuals who used solid fuels at baseline but switched to clean fuels during follow-up. We also examined associations with prospective health events (any respiratory diseases, respiratory disease hospitalizations, and all-cause mortality).

RESULTS

In adjusted cross-sectional models, use of solid fuel in comparison with clean fuels was associated with lower FEV1 of -17.5mL (95% CI: -32.7, -2.3) and FVC of -14.4mL (95% CI: -32.0, 3.2), but not FEV1/FVC. In longitudinal analyses, individuals who switched from solid fuels to clean cooking fuels during follow-up (n=3,901, 46% of those using solid fuel at baseline), showed no differences in the annual rate of change in FEV1 or FVC, but had small improvements in FEV1/FVC change (0.2% per year, 95% CI: 0.03, 0.3). Individuals who switched from solid to clean fuels had a decreased hazard ratio for respiratory events of 0.76 (95% CI: 0.57, 1.00) in comparison with persistent solid fuel users, which was not attenuated by lung function measures.

CONCLUSION

We observed modest associations between HAP exposure and lung function, lung function change, and respiratory disease and mortality. https://doi.org/10.1289/EHP11179.

Self-Reported Primary Cooking Fuels Use and Risk of Chronic Digestive Diseases: A Prospective Cohort Study of 0.5 Million Chinese Adults

BACKGROUND

Household air pollution (HAP) from inefficient combustion of solid fuels is a major health concern worldwide. However, prospective evidence on the health impacts of solid cooking fuels and risks of chronic digestive diseases remains scarce.

OBJECTIVES

We explored the effects of self-reported primary cooking fuels on the incidence of chronic digestive diseases.

METHODS

The China Kadoorie Biobank recruited 512,726 participants 30-79 years of age from 10 regions across China. Information on primary cooking fuels at the current and previous two residences was collected via self-reporting at baseline. Incidence of chronic digestive diseases was identified through electronic linkage and active follow-up. Cox proportional hazards regression models were used to estimate adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) for the associations of self-reported long-term cooking fuel patterns and weighted duration of self-reported solid cooking fuel use with chronic digestive diseases incidence. Linear trend was tested by assigning the medians of weighted duration in each group and then taking those as continuous variables in the models. Subgroup analyses were undertaken across the baseline characteristics of participants.

RESULTS

During 9.1±1.6 y of follow-up, 16,810 new cases of chronic digestive diseases were documented, among which 6,460 were diagnosed as cancers. Compared with long-term cleaner fuel use, self-reported long-term use of solid cooking fuels (i.e., coal, wood) was associated with elevated risks of chronic digestive diseases (HR=1.08; 95% CI: 1.02, 1.13), including nonalcoholic fatty liver disease (NAFLD) (HR=1.43; 95% CI: 1.10, 1.87), hepatic fibrosis/cirrhosis (HR=1.35; 95% CI: 1.05, 1.73), cholecystitis (HR=1.19; 95% CI: 1.07, 1.32), and peptic ulcers (HR=1.15; 95% CI: 1.00, 1.33). The longer the weighted duration of self-reported solid cooking fuel use, the higher the risks of chronic digestive diseases, hepatic fibrosis/cirrhosis, peptic ulcers, and esophageal cancer (pTrend<0.05). The aforementioned associations were modified by sex and body mass index (BMI). Positive associations of always solid cooking fuel use with chronic digestive disease, hepatic fibrosis/cirrhosis, NAFLD, and cholecystitis were observed among women but not men. The longer the weighted duration of self-reported solid cooking fuel use, the higher the risk of NAFLD among those with a BMI ≥28 kg/m2.

DISCUSSION

Long-term self-reported solid cooking fuels use was associated with higher risks of chronic digestive diseases. The positive association of HAP from solid cooking fuels with chronic digestive diseases indicates for an imminent promotion of cleaner fuels as public health interventions. https://doi.org/10.1289/EHP10486.

Kitchen ventilation attenuated the associations of solid fuel use and long duration for cooking with the increased prevalence of normocytic anemia

Evidence on the potential risk factors of normocytic anemia, the most prevalent morphology subtype of anemia, was scarce to date. The purpose of this study is to investigate the association of cooking fuel use or daily cooking duration with normocytic anemia and further explore the modification effect of mechanical ventilation. Participants totaling 29,448 from the Henan Rural Cohort were included in this study. Normocytic anemia was defined by hemoglobin (based on the World Health Organization criteria) and mean corpuscular volume. Cooking-related data was collected by questionnaire, and the average daily cooking duration was calculated by the weekly cooking frequency and the cooking duration of each meal. Logistic regression models were employed to derive the combined and independent associations of cooking fuel type and daily cooking duration with normocytic anemia and the modification effect of ventilation. Compared with people who never cooked, both clean fuel and solid fuel users were significantly associated with increased prevalent normocytic anemia [OR (95% CI) = 1.196 (1.014, 1.411) and 1.335 (1.105, 1.614), respectively], and the effect estimates on normocytic anemia risk were 1.260 (1.043, 1.523), 1.320 (1.104, 1.578), and 1.310 (1.081, 1.587) in participants who daily cooked < 1 h/day, 1-2 h/day, and ≥ 2 h/day, respectively. These relationships were attenuated in subjects with mechanical ventilation (All P < 0.05). Cooking with solid fuel or for a long duration are independently associated with prevalent normocytic anemia in rural population, and mechanical ventilation could attenuate these associations. Future efforts to reduce the burden of anemia could target the universal use of ventilation and solid fuel use or cooking duration reduction.Clinical trial registration: The Henan Rural Cohort Study has been registered at Chinese Clinical Trial Register (Registration number: ChiCTR-OOC-15006699). Date of registration: 06 July, 2015. http://www.chictr.org.cn/showproj.aspx?proj=11375.

Knowledge, attitude, and practice toward disease prevention among a high-risk population for chronic obstructive pulmonary disease: A cross-sectional study

Objective

This study aimed to describe the current situation of knowledge, attitude, and practice (KAP) of chronic obstructive pulmonary disease (COPD) prevention among a high-risk population for COPD.

Methods

A cross-sectional survey was conducted. A total of 241 participants at risk of COPD were selected who visited the respiratory outpatient department of a Class A tertiary hospital in Chongqing, China from January to December 2021. A self-developed COPD prevention KAP assessment was used for evaluation which included knowledge (21 items), attitude (9 items), and practice (9 items) three dimension, 39 items.

Results

The average overall KAP score was 68.29 ± 12.91, with scores for the knowledge, attitude, and practice dimension was 68.75 ± 18.07, 71.13 ± 15.09 and 65.00 ± 20.93, respectively. Among the people at risk of COPD, 76.8% experienced a moderate level of KAP toward COPD prevention, while 22.0% were at a poor level. Significant differences in the KAP scores were based on gender, educational level, occupation, type of medical insurance, smoking, and passive smoking status (P < 0.05). The male COPD high-risk group has better KAP toward COPD prevention than the female group (P < 0.05). The knowledge and attitude of COPD prevention present worse in people with a high risk of COPD aged 70 or above, primary school and below educational level, and farmers (P < 0.05). Smoking and passive smoking groups have higher recognition of the knowledge but the lower practice of COPD prevention (P < 0.05).

Conclusion

The participants with a high risk of COPD had a moderate level of KAP for COPD prevention, in which the understanding and action on vaccination and lung function test was weak, but an active attitude for health. It is necessary to implement tailored health education interventions to their characteristics to reduce the incidence and development of COPD.

Impacts of solid fuel use versus smoking on life expectancy at age 30 years in the rural and urban Chinese population: a prospective cohort study

Background

The impact of solid fuel use on life expectancy (LE) in less-developed countries remains unclear. We aimed to evaluate the potential impact of household solid fuel use on LE in the rural and urban Chinese population, with the effect of smoking as a reference.

Methods

We used data from China Kadoorie Biobank (CKB) of 484,915 participants aged 30-79 free of coronary heart disease, stroke, or cancer at baseline. Analyses were performed separately for solid fuel use for cooking, solid fuel use for heating, and smoking, with participants exposed to the other two sources excluded. Solid fuels refer to coal and wood, and clean fuels refer to electricity, gas, and central heating. We used a flexible parametric Royston-Parmar model to estimate hazard ratios of all-cause mortality and predict LE at age 30.

Findings

Totally, 185,077, 95,228, and 230,995 participants were included in cooking-, heating-, and smoking-related analyses, respectively. During a median follow-up of approximately 12.1 years, 12,725, 7,531, and 18,878 deaths were recorded in the respective analysis. Compared with clean fuel users who reported cooking with ventilation, participants who used solid fuels with ventilation and without ventilation had a difference in LE (95% confidence interval [CI]) at age 30 of -1.72 (-2.88, -0.57) and -2.62 (-4.16, -1.05) years for men and -1.33 (-1.85, -0.81) and -1.35 (-2.02, -0.67) years for women, respectively. The difference in LE (95% CI) for heating was -2.23 (-3.51, -0.95) years for men and -1.28 (-2.08, -0.48) years for women. In rural men, the LE reduction (95% CI) related to solid fuel use for cooking (-2.55; -4.51, -0.58) or heating (-3.26; -6.09, 0.44) was more than that related to smoking (-1.71; -2.54, -0.89). Conversely, in urban men, the LE reduction (95% CI) related to smoking (-3.06; -3.56, -2.56) was more than that related to solid fuel use for cooking (-1.28; -2.61, 0.05) and heating (-1.90; -3.16, -0.65). Similar results were observed in women but with a smaller magnitude.

Interpretation

In this Chinese population, the harm to LE from household use of solid fuels was greater than that from smoking in rural residents. Conversely, the negative impact of smoking was greater than solid fuel use in urban residents. Our findings highlight the complexity and diversity of the factors affecting LE in less-developed populations.

Funding

National Natural Science Foundation of China, National Key R&D Program of China, Kadoorie Charitable Foundation, UK Wellcome Trust.

Environment and chronic disease in rural areas of Heilongjiang, China (ECDRAHC)

PURPOSE

Environmental factors such as long-term exposure to cold can increase the risk of chronic diseases. However, few studies have focused on the impact of environmental factors and lifestyle changes on chronic diseases. To fully explore the association between exposure to environmental factors and the prevalent risk of various chronic diseases, we conducted a large cohort study (Environment and Chronic Disease in Rural Areas of Heilongjiang, China (ECDRAHC)). The ECDRAHC collected detailed questionnaire data covering 10 sections, physical measurements and blood and urine samples. In this study, we describe the design and implementation of the cohort study and present the findings for the first 10 000 participants.

PARTICIPANTS

The ECDRAHC study was carried out in rural areas where the annual average temperature is 2.9°C, and aimed to recruit 40 000 participants who are long-term residents aged 35-74 years. The participants will be followed up every 5 years. Currently, ECDRAHC has reached 26.7% (n=10 694) of the targeted population.

FINDINGS TO DATE

A total of 10 694 adults aged 35-74 years were recruited, including 61.7% women. The prevalence of current smokers was 46.8% in men and 35.4% in women. The mean blood pressure was 140.2/89.9 mm Hg and 135.7/85.0 mm Hg in men and women, respectively. The mean body mass index was 24.74 kg/m² in men and 24.65 kg/m² in women, with >7.3% being obese (>30 kg/m²). The main non-communicable diseases found in phase 1 were hypertension, diabetes, hypertriglyceridaemia and metabolic syndrome, with a higher prevalence of 51.0%, 21.6%, 46.8% and 42.6%, respectively.

FUTURE PLANS

We plan to complete the follow-up for the first phase of the ECDRAHC in 2024. The second and third phase of the cohort will be carried out steadily, as planned. This cohort will be used to investigate the relationship between environmental factors, lifestyle, and genetic and common chronic diseases.

Association between Fish Consumption and Risk of Chronic Obstructive Pulmonary Disease among Chinese Men and Women: an 11-Year Population-Based Cohort Study

BACKGROUND

Epidemiological evidence on the relation between fish consumption and chronic obstructive pulmonary disease (COPD) is limited, especially among Chinese.

OBJECTIVES

The aim was to explore the prospective association between fish consumption and COPD among a large population-based Chinese cohort.

METHODS

The China Kadoorie Biobank recruited over 0.5 million participants from 10 geographically diverse regions across China from 2004 to 2008. Consumption frequency of fish at baseline was assessed by a validated food-frequency questionnaire. A total of 169,188 men and 252,238 women who had no prior COPD or other major chronic diseases at baseline were included in our analyses. Cox proportional hazard models were used to estimate HRs and 95% CIs for fish consumption categories in relation to incident COPD.

RESULTS

During a median follow-up of 11.1 y, 11,292 incident COPD cases were documented. Fish consumption was inversely associated with COPD risk among women, with a 17% reduction in risk for participants who consumed fish ≥4 d/wk compared with nonconsumption (HR: 0.83; 95% CI: 0.70, 0.99; P-trend = 0.017), whereas we did not observe such a dose-response relation among men (HR: 0.89; 95% CI: 0.76, 1.05; P-trend = 0.373). The joint analysis showed that COPD risk was 38% and 48% lower in men and women who consumed fish ≥4 d/wk and had a healthy lifestyle [having ≥4 of the following healthy lifestyle factors: not smoking currently; never or rarely drinking alcohol; adequate physical activity; BMI (kg/m2): 18.5-23.9; normal waist circumference; reasonable diet], compared with participants with fish consumption <4 d/wk and an unhealthy lifestyle (≤1 factors).

CONCLUSIONS

Higher fish consumption was associated with lower COPD risk among Chinese women but not men. This association was independent of lifestyle factors. Eating adequate fish with an overall healthy lifestyle might help lower the risk of COPD.

Solid Fuel Use and the Progression of Multimorbidity in Middle-Aged Chinese Participants: A Prospective Cohort Study

Objectives: This study aimed to examine the association of solid fuel use for cooking and heating with the progression of multimorbidity. Methods: A total of 5,437 participants from the China Health and Retirement Longitudinal Study were included. Multivariate logistic regression models were used to estimate the odds ratios (ORs) and 95% confidence intervals (CIs) for the associations of the independent and joint effects of solid fuel use for cooking and heating with the progression of multimorbidity. Results: The proportion of participants reporting solid fuel use for both cooking and heating was 59.0% at baseline. Solid fuel use for both cooking and heating was associated with the progression of multimorbidity (adjusted OR: 1.42, 95% CI: 1.19-1.70), compared with clean fuel use for both. Conclusion: Solid fuel use for cooking and heating play an important role in the progression of multimorbidity. Therefore, solid fuel reduction should be considered in developing multimorbidity control and prevention programmes.

Associations of Household Solid Fuel Use With Falls and Fall-Related Injuries in Middle-Aged and Older Population in China: A Cohort Study

Objective: This study evaluated the associations of solid fuels with incidence of falls and fall-related injuries. Methods: Data were taken from wave 1∼4 of the China Health and Retirement Longitudinal Study, including 15,651 participants aged 45 years and older. Modified Poisson regression was used to examine the associations of solid fuels with falls and fall-related injuries. Results: Modified Poisson regression analysis showed that solid fuels users for cooking had an increasing incidence of falls and fall-related injuries, with RR of 1.211 (95% CI: 1.124, 1.305) and 1.248 (95% CI: 1.107, 1.408); for heating had an incidence, with RR of 1.178 (95% CI: 1.062, 1.306) and 1.134 (95% CI: 0.963, 1.335); combined for cooking and heating, with RR of 1.247 (95% CI: 1.105, 1.408) and 1.185 (95% CI: 0.982, 1.431). Conclusion: Our study suggests that solid fuel use is associated with a higher incidence of falls and fall-related injuries among adults aged 45 years and older in China. It is necessary to restrict solid fuel use to reduce household air pollution and make stronger environmental protection policies to improve household environment.

Association between pneumonia hospitalisation and long-term risk of cardiovascular disease in Chinese adults: A prospective cohort study

BACKGROUND

Lower respiratory tract infections, including pneumonia, have been associated with short-term increased risk of cardiovascular disease (CVD). However, there is only limited evidence about the long-term impact of pneumonia on the cardiovascular system beyond one year.

METHODS

We conducted a prospective matched cohort study based on data from the China Kadoorie Biobank study of 482,017 adults who were enrolled between June 25, 2004, and July 15, 2008, and were free of CVD at baseline and before pneumonia hospitalization. A total of 24,060 patients hospitalised with pneumonia were identified until December 31, 2018, and were matched on age, sex, urban or rural areas, and decile of the frailty index to 223,875 controls. We used the piecewise Cox proportional hazards model to estimate the hazard ratios (HRs) and their 95% confidence intervals (CIs) for pre-specified incident CVD outcomes, including ischaemic heart disease (IHD), arrhythmia, heart failure (HF), ischaemic stroke (IS), and hemorrhagic stroke (HS), at various time intervals through 10 years after pneumonia hospitalization.

FINDINGS

Of the 247,935 pneumonia cases and controls included, the mean age (standard deviation) was 53.5 (10.4), and 40.8% (101,159) were men. During follow-up, 2389 (9.9%) pneumonia cases developed IHD, 489 (2.0%) cases developed arrhythmia, 545 (2.3%) cases developed HF, 1764 (7.3%) cases developed IS, and 348 (1.4%) cases developed HS. After adjustment for sociodemographic characteristics, lifestyle factors, health status and medication, underlying conditions, and family history of CVD, the elevated CVD risk was highest within the first 30 days after pneumonia hospitalisation, with subsequent risk reductions varying by subtypes. The elevated risk remained until the eighth year after pneumonia hospitalisation for IHD, arrhythmia, and HF, with HRs (95% CIs) of 1.48 (1.13-1.93), 2.69 (1.70-4.25), and 4.36 (2.86-6.64), respectively. The risk of stroke associated with pneumonia hospitalisation remained elevated until the seventh year for IS (HR = 1.30; 95% CI: 1.04-1.63), and until the second year for HS (1.39; 1.07-1.80). The above associations were consistently observed across various characteristics of the participants.

INTERPRETATION

In middle-aged and older Chinese adults, pneumonia hospitalisation was associated with short- and long-term CVD risk, with the elevated risk of certain CVD outcomes persisting for up to 8 years.

FUNDING

National Natural Science Foundation of China, the National Key R&D Program of China, the Chinese Ministry of Science and Technology, the Kadoorie Charitable Foundation in Hong Kong, the UK Wellcome Trust.

Associations of cooking fuel types and daily cooking duration with sleep quality in rural adults: Effect modification of kitchen ventilation

BACKGROUND

Associations of combined different cooking fuel types and cooking duration with sleep quality were scarcely reported. This study aimed to explore the associations of exposure to household air pollution (HAP) from different cooking fuel types and cooking duration with sleep quality and examine the effect modification of kitchen ventilation on these associations.

METHODS

A total of 28,135 eligible participants were obtained from the Henan rural cohort study. Sleep quality was assessed by the Pittsburgh sleep quality index (PSQI), and participants with a PSQI score > 5 were identified as having poor sleep quality. A questionnaire was used to collect the cooking fuel types, cooking frequency, cooking duration, and kitchen ventilation. The average daily cooking duration was calculated as the cooking frequency per week multiplied by the cooking duration for each meal divided by 7.

RESULTS

Both domestic fuel use and cooking duration were positively related to poor sleep quality. The solid fuel users with a cooking duration ≥1.5 h/day had a higher prevalence of poor sleep quality (OR: 1.390, 95% CI: 1.233, 1.567), relative to those who never cooked. Notably, the estimated OR and 95% CI for poor sleep quality of clean fuel users with a cooking duration <1.5 h/day plus mechanical or natural ventilation versus those who never cooked was 1.05 (0.933, 1.187) or 1.306 (1.163, 1.466) and these associations were modified by kitchen ventilation.

CONCLUSION

Positive associations of combined different cooking fuel types and cooking duration with the prevalence of poor sleep quality were attenuated by kitchen ventilation, implying that installing mechanical ventilation may be an effective measure to improve sleep quality in low- and middle-income countries. These results need to be confirmed by future studies, which measure HAP more accurately using personal monitoring devices or behavior diaries.

The Effect of Kitchen Ventilation Modification on Independent and Combined Associations of Cooking Fuel Type and Cooking Duration with Suicidal Ideation: A Cross-Sectional Study

Although household air pollution (HAP) is associated with an increased risk of mental disorders, evidence remains scarce for the relationship between HAP and suicidal ideation. A total of 21,381 qualified participants were enrolled on the Henan Rural Cohort Study. HAP information including cooking fuel type, cooking duration and kitchen ventilation was collected by questionnaires. Suicidal ideation was evaluated by item nine of the Patient Health Questionnaire-9 (PHQ-9). Independent and combined associations of cooking fuel type and cooking duration with suicidal ideation were explored by logistic regression models. Analyses were conducted in different kitchen ventilation groups to detect the potential effect modification. The adjusted odds ratio (OR) and 95% confidence interval (95% CI) of solid fuel users versus clean fuel users for suicidal ideation was 1.37 (1.16, 1.62), and the risk of suicidal ideation increased by 15% (95% CI: 5%, 26%) for each additional hour of the cooking duration. Participants cooking with solid fuel for long durations were related to the highest risk of suicidal ideation (OR (95% CI): 1.51 (1.22, 1.87)). However, all these associations were not observed in those cooking with mechanical ventilation. Mechanical ventilation ameliorated relationships between solid fuel use and long-duration cooking with suicidal ideation.

Overall and cause-specific mortality rates among men and women with high exposure to indoor air pollution from the use of smoky and smokeless coal: a cohort study in Xuanwei, China

OBJECTIVES

Never-smoking women in Xuanwei (XW), China, have some of the highest lung cancer rates in the country. This has been attributed to the combustion of smoky coal used for indoor cooking and heating. The aim of this study was to evaluate the spectrum of cause-specific mortality in this unique population, including among those who use smokeless coal, considered 'cleaner' coal in XW, as this has not been well-characterised.

DESIGN

Cohort study.

SETTING

XW, a rural region of China where residents routinely burn coal for indoor cooking and heating.

PARTICIPANTS

Age-adjusted, cause-specific mortality rates between 1976 and 2011 were calculated and compared among lifetime smoky and smokeless coal users in a cohort of 42 420 men and women from XW. Mortality rates for XW women were compared with those for a cohort of predominately never-smoking women in Shanghai.

RESULTS

Mortality in smoky coal users was driven by cancer (41%), with lung cancer accounting for 88% of cancer deaths. In contrast, cardiovascular disease (CVD) accounted for 32% of deaths among smokeless coal users, with 7% of deaths from cancer. Total cancer mortality was four times higher among smoky coal users relative to smokeless coal users, particularly for lung cancer (standardised rate ratio (SRR)=17.6). Smokeless coal users had higher mortality rates of CVD (SRR=2.9) and pneumonia (SRR=2.5) compared with smoky coal users. These patterns were similar in men and women, even though XW women rarely smoked cigarettes. Women in XW, regardless of coal type used, had over a threefold higher rate of overall mortality, and most cause-specific outcomes were elevated compared with women in Shanghai.

CONCLUSIONS

Cause-specific mortality burden differs in XW based on the lifetime use of different coal types. These observations provide evidence that eliminating all coal use for indoor cooking and heating is an important next step in improving public health particularly in developing countries.

Association between pregnancy and pregnancy loss with COPD in Chinese women: The China Kadoorie Biobank study

Background

Chronic obstructive pulmonary disease (COPD) is an inflammatory lung disease characterized by airflow blockage. Pregnancy and pregnancy loss may be related to an elevated risk of COPD, although studies have yet to report on this association. Hence, this study aims to investigate the association between pregnancy and pregnancy loss with the risk of COPD among Chinese women.

Methods

Data on 302,510 female participants from the China Kadoorie Biobank were utilized for this study. Multivariable logistic regression, stratified by sociodemographic and lifestyle factors, was employed to obtain the odds ratio (ORs) and 95% confidence intervals (CIs) for the association between pregnancy and pregnancy loss with COPD.

Results

Pregnancy loss was significantly associated with increased risk of COPD (OR 1.19, 95% CI 1.13-1.25), specifically, spontaneous (OR 1.19, 95% CI 1.11-1.29) and induced abortion (OR 1.18, 95% CI 1.12-1.25). Stillbirth, however, was not significantly associated with the risk of COPD (OR 1.09, 95% CI 0.99-1.20). Increasing number of pregnancy losses was associated with increasing risk of COPD (one pregnancy loss: OR 1.14, 95% CI 1.07-1.21, two or more pregnancy loss: OR 1.25, 95% CI 1.17-1.32, and each additional pregnancy loss: OR 1.06, 95% CI 1.03-1.09). A single pregnancy was significantly associated with reduced risk of COPD (OR 0.75, 95% CI 0.59-0.97), although each additional pregnancy was significantly associated with increased risk of COPD (OR 1.03, 95% CI 1.01-1.04).

Conclusion

Pregnancy loss, in particular, spontaneous and induced abortions are associated with increased risk of COPD among Chinese women. A single pregnancy, however, demonstrated protective effects.

Cooking or heating with solid fuels increased the all-cause mortality risk among mid-aged and elderly People in China

BACKGROUND

Our study aimed to explore the associations between solid fuels burning for either heating or cooking and all-cause mortality based on 2859 participants from the China Health and Retirement Longitudinal Study during 2011-2018.

METHODS

Logistic regression models were performed to estimate the risk for all-cause mortality between different types of fuels in the current longitudinal study. Furthermore, the combined impacts of applying solid fuels for both cooking and heating and the effect among those who switched types of fuels in cooking or heating during follow-up were also analyzed. Interaction and stratification analysis by covariables was applied further to explore the relationship between fuel burning and all-cause mortality.

RESULTS

After full-adjustment, usage of solid fuels was associated with higher all-cause mortality (for heating: OR = 1.93, 95% CI = 1.25, 3.00; for cooking: OR = 1.76, 95% CI = 1.10, 2.82). Using solid fuels for both cooking and heating (OR = 2.36; 95% CI, 1.38, 4.03) was associated with a higher risk of all-cause mortality, while using solid fuels with a single purpose was not (OR = 1.52; 95% CI, 0.90, 2.55). Protective tendencies were detected in switching solid to clean fuel for cooking (OR = 0.62; 95% CI, 0.32, 1.17) and heating (OR = 0.62; 95% CI, 0.35, 1.10).

CONCLUSION

Either cooking or heating with solid fuels increases the risk of all-cause mortality among Chinese mid-aged and aging people in the urban area of China.

Gaseous Air Pollutants and Respirable Crystalline Silica Inside and Outside Homes at Brick Kilns in Bhaktapur, Kathmandu Valley, Nepal

Household and ambient air pollution remain public health problems in much of the world. Brick kiln employees in Nepal may be particularly at risk of high air pollution exposures and resulting health effects due to high levels of outdoor air pollution, substandard housing, and indoor biomass cooking. We conducted a cross-sectional study of indoor and outdoor air pollution concentrations at workers' homes at four fixed chimney Bull's trench brick kilns in Bhaktapur, Kathmandu Valley, Nepal. We measured air concentrations of carbon monoxide (CO), carbon dioxide (CO₂), nitrogen dioxide (NO₂), sulfur dioxide (SO₂), and respirable crystalline silica (SiO₂; cristobalite, quartz, tridymite) using established methods and conducted a survey about characteristics of homes or samples that may be associated with air pollution concentrations. Geometric mean concentrations of CO, CO₂, and SiO₂ (quartz) were 0.84 ppm, 1447.34 ppm, and 6.22 µg/m³, respectively, whereas concentrations of all other air pollutants measured below lower detection limits. Most characteristics of homes or samples were not associated with air pollution concentrations. We found a positive association between the variable how long lived in house and SiO₂ (quartz) concentrations, which may reflect sustained take-home exposure to SiO₂ (quartz) over time. Interventions should focus on administrative controls to reduce take-home exposure to SiO₂ (quartz) in this population.

Kitchen ventilation alleviated adverse associations of domestic fuel use and long-duration cooking with platelet indices as biomarkers of cardiovascular diseases

BACKGROUND

Abnormal platelet activity is considered as a potential mechanism of cardiovascular diseases (CVDs) related to household air pollution (HAP). However, evidence remains lacking for the association of HAP with platelet activity in low-middle income countries.

METHODS

27,349 individuals were obtained from the Henan Rural Cohort Study. A questionnaire was used to collect data on cooking fuel types, cooking frequency and time as well as kitchen ventilation which indirectly reflected HAP. Platelet activity was indicated by platelet count (PLT), platelet distribution width (PDW), mean platelet volume (MPV), ratio of mean platelet volume to platelet count (MPVP), platelet-large cell ratio (P-LCR) and plateletcrit (PCT). Associations of HAP with platelet activity were assessed by generalized linear mixed models.

RESULTS

Compared with the ones without cooking, participants who cooking using solid fuel, clean fuel, short- and long-duration cooking were at a high risk for increased platelet size (PDW, MPV, MPVP and P-LCR) but decreased PLT and PCT; long-duration cooking participants with non-using exhaust hood/extractor by solid fuel use were associated with a 0.259 f. (95%CI: 0.100, 0.418 fL), 0.115 f. (95%CI: 0.050, 0.181 fL), 0.001 (95%CI: 0.000, 0.003) and 0.928% (95%CI: 0.425, 1.431%) increment in PDW, MPV, MPVP and P-LCR values and these associations were prominent in women relative than that in men.

CONCLUSION

Using exhaust hood/extractor attenuated the positive associations of solid fuel use and long-duration cooking with increased platelet size in all participants and these associations were prominent in women, indicating that improving kitchen ventilation may be an effective strategy to reduce platelet dysfunction related to HAP, especially for women.

Tobacco smoking and solid fuels for cooking and risk of liver cancer: A prospective cohort study of 0.5 million Chinese adults

Previous research found tobacco smoking and solid fuel use for cooking to increase the risk of chronic liver disease mortality, but previous cohort studies have not investigated their independent and joint associations with liver cancer incidence in contemporary China. The China Kadoorie Biobank (CKB) study recruited 0.5 million adults aged 30 to 79 years from 10 areas across China during 2004 to 2008. Participants reported detailed smoking and fuel use information at baseline. After an 11.1-year median follow-up via electronic record linkage, we recorded 2997 liver cancer cases. Overall, 29.4% participants were current smokers. Among those who cooked at least once per month, 48.8% always used solid fuels (ie, coal or wood) for cooking. Tobacco smoking and solid fuel use for cooking were independently associated with increased risks of liver cancer, with hazard ratios (95% confidence intervals [CIs]) of 1.28 (1.15-1.42) and 1.25 (1.03-1.52), respectively. The more cigarettes consumed each day, the earlier the age of starting smoking or the longer duration of solid fuels exposure, the higher the risk (Ptrend  < .001, =.001, =.018, respectively). Compared with never smokers who had always used clean fuels (ie, gas or electricity), ever-smokers who had always used solid fuels for cooking had a 67% (95% CIs: 1.29-2.17) higher risk. Among Chinese adults, tobacco smoking and solid fuel use for cooking were independently associated with higher risk of liver cancer incidence. Stronger association was observed with higher number of daily cigarette consumption, the earlier age of starting smoking and longer duration of solid fuel use.

Exposure to indoor air pollution from solid fuel and its effect on depression: a systematic review and meta-analysis

A growing body of research has investigated the relationship between indoor air pollution from solid fuel and depression risk. Our study aimed to elucidate the relationship between indoor air pollution from solid fuel and depression in observational studies. The effect of indoor air pollution on depression was estimated using pooled odds ratios (ORs) with 95% confidence intervals (CIs). Heterogeneity was evaluated by the I-squared value (I²), and the random-effects model was adopted as the summary method. We finalized nine articles with 70,214 subjects. The results showed a statistically positive relationship between the use of household solid fuel and depression (OR = 1.22, 95% CI = 1.09-1.36). Subgroup analysis based on fuel type groups demonstrated that indoor air pollution from solid fuel was a higher risk to depression (OR = 1.24, 95% CI = 1. 10-1.39; I² = 67.0%) than that from biomass (OR = 1.18, 95% CI = 0.96-1.45; I² = 66.5%). In terms of fuel use, the use of solid fuel for cooking and heating increased depression risk, and the pooled ORs were 1.21 (95% CI = 1.08-1.36) and 1.23 (95% CI = 1.13-1.34). Exposure to indoor air pollution from solid fuel might increase depression risk.

Early-Life Exposure to Malnutrition From the Chinese Famine on Risk of Asthma and Chronic Obstructive Pulmonary Disease in Adulthood

Objectives

Intrauterine malnutrition has a long-term effect on respiratory and lung function. However, few studies have explored the association between early-life exposure to famine with asthma and chronic obstructive pulmonary disease (COPD) in adulthood. Therefore, we aimed to investigate the association of early-life exposure to the Chinese famine of 1959–1962 with asthma and COPD later in life.

Methods

This national population-based study included 6,771 participants from the baseline survey of the China Health and Retirement Longitudinal Study (CHARLS) who were born around the time of the Chinese famine. The famine exposure groups were determined according to the participants' birth year as non-exposed (1964–1967), fetal-exposed (1959–1962), preschool-exposed (1954–1957), and school-age exposed (1950–1953). Information about the demographic characteristics, self-reported doctor-diagnosed asthma and COPD, behavior and lifestyles, and indoor pollution were collected using validated questionnaires. In addition, peak expiratory flow (PEF) was measured to assess pulmonary function. Multivariable logistic regression and generalized linear mixed models were performed to explore the risk of adult asthma and COPD, PEF changes during various famine exposure periods compared with the non-exposed group. Stratified and sensitivity analyses were conducted to examine the modification and robustness of the association.

Results

The prevalence of doctor-diagnosed asthma and COPD was 2.8 and 8.1%, respectively. Compared with the non-exposed group, the risk was significantly higher in the fetal-exposed group for asthma [adjusted odds ratio, (aOR) = 1.87, 95% confidence interval (CI):1.14–3.07] and the school-age exposed group [1.30 (1.00–1.69)] for COPD after controlling for confounders. Furthermore, we observed that fetal exposure to famine was significantly associated with a decrement of PEF in adulthood [β = −11.38 (−22.75 to −0.02)] compared with the non-exposed group. Stratified analyses showed that the association of asthma was stronger in men, who resided in severely famine-affected areas, smoked, and used solid fuels for cooking. No clearly consistent association was observed for subsequent COPD.

Conclusions

Our results suggest that fetal exposure to the Chinese famine is significantly associated with the increased risk of asthma in adulthood. Future prospective studies are warranted to examine the association and mechanisms.

Global disease burden of COPD from 1990 to 2019 and prediction of future disease burden trend in China

OBJECTIVES

This study aimed to assess and predict the disease burden attributable to chronic obstructive pulmonary disease (COPD) in a timely, comprehensive, and reliable manner, thereby mitigating the health hazards of COPD.

STUDY DESIGN AND METHODS

Data on the disease burden owing to COPD from 1990 to 2019 were extracted from the Global Burden of Disease (GBD) Study 2019. Linear regression analysis was used to calculate the estimated annual percentage change (EAPC) in the age-standardized rates. Non-parametric tests were used for subgroup analysis. The Bayesian age-period-cohot (BAPC) model integrated nested Laplace approximations to predict the disease burden over the next 25 years. Sensitivity analysis was performed using the Norpred APC model.

RESULTS

Globally, the COPD-related age-standardized incidence rate decreased from 216.48/100,000 in 1990 to 200.49/100,000 in 2019, with an EAPC of -0.33. But the number of new cases increased from 8,722,966 in 1990 to 16, 214, 828 in 2019. Trends in prevalence, deaths, and disability-adjusted life years (DALYs) were the same as incidence. There were significant differences in disease burden between the genders and all age groups (P < 0.05) in China. The projections suggested that the COPD-related number of new cases and deaths in China would increase by approximately 1.5 times over the next 25 years.

CONCLUSIONS

The number of incidence, prevalence, deaths, and DALYs had all increased in China in the past and would continue to grow over the next 25 years. Therefore, measures should be taken to target risk factors and high-risk groups.

The hospitalization burden of all-cause pneumonia in China: A population-based study, 2009-2017

BACKGROUND

Pneumonia represents a public health problem of substantial health and economic burden. However, the evidence on the burden of adult pneumonia is limited in China.

METHODS

The China Kadoorie Biobank recruited 512,725 participants aged 30-79 years from five urban and five rural areas during 2004-2008. The current analyses included 506,086 participants who were alive in 2009. Pneumonia hospitalizations were ascertained through the health insurance system until December 31, 2017. Generalized linear models were used to examine the secular trends and regional and population variations in pneumonia hospitalization rate, mean length of hospital stay (LOS), and 30-day case fatality rate (CFR).

FINDINGS

A total of 27,879 participants with 36,567 pneumonia hospitalizations were identified with a mean follow-up time of 8·9 years. The unadjusted hospitalization rate was 8·4 (95% confidence interval [CI]: 8·3, 8·6) per 1000 person-years, with an increase of 15·5% annually from 4·2 (3·9, 4·4) in 2009 to 10·9 (10·6, 11·3) in 2017, after adjusting for age, sex, study area. The mean LOS was 8·8 (95% CI: 8·7, 8·9) days, with a slight decrease of 1·0% annually from 2009 to 2017. The average 30-day CFR remained practically unchanged at 2·4 (95% CI: 2·2, 2·5) deaths per 100 admissions. A clear seasonal pattern of pneumonia hospitalization rate was observed, and the hospitalization rate and CFR differed across regions and subpopulations of different ages and underlying conditions.

INTERPRETATION

There was an increasing hospitalization burden of pneumonia in Chinese adults, especially for adults aged ≥60 years or those with underlying conditions.

FUNDING

The National Natural Science Foundation of China, the Kadoorie Charitable Foundation, the National Key R&D Program of China, the Chinese Ministry of Science and Technology.

TRANSLATED ABSTRACT IN CHINESE

This translation in Chinese was submitted by the authors and we reproduce it as supplied. It has not been peer reviewed. Our editorial processes have only been applied to the original abstract in English, which should serve as reference for this manuscript. :, ., .:(China Kadoorie Biobank)2004-2008555030-79.506,086200911.20091120171231.,30,.:8.9, 27,879, 36,567.8.4 (95% CI:8.3, 8.6)/1000, ,, 20094.2 (3.9, 4.4)201710.9 (10.6, 11.3), 15.5%.8.8(95% CI:8.7, 8.9), 1.0%.30, 2.4(95% CI:2.2, 2.5)/100.;,, 30.:, ≥60.

Chronic obstructive pulmonary disease in never-smokers: risk factors, pathogenesis, and implications for prevention and treatment

Chronic obstructive pulmonary disease (COPD) was traditionally thought to be caused by tobacco smoking. However, recognition of the importance of non-smoking-related risk factors for COPD has increased over the past decade, with evidence on the burden, risk factors, and clinical presentations of COPD in never-smokers. About half of all COPD cases worldwide are due to non-tobacco-related risk factors, which vary by geographical region. These factors include air pollution, occupational exposures, poorly controlled asthma, environmental tobacco smoke, infectious diseases, and low socioeconomic status. Impaired lung growth during childhood, caused by a range of early-life exposures, is associated with an increased risk of COPD. Potential mechanisms for the pathogenesis of COPD in never-smokers include inflammation, oxidative stress, airway remodelling, and accelerated lung ageing. Compared with smokers who develop COPD, never-smokers with COPD have relatively mild chronic respiratory symptoms, little or no emphysema, milder airflow limitation, and fewer comorbidities; however, exacerbations can still be frequent. Further research-including epidemiological, translational, clinical, and implementation studies-is needed to address gaps in understanding and to advance potential solutions to reduce the burden of COPD in never-smokers.

Effect modification of kitchen ventilation on the associations of solid fuel use and long-duration cooking with the increased prevalence of depressive and anxiety symptoms: The Henan Rural Cohort Study

Although solid fuel use for cooking is linked to an increased risk for depression, there is limited evidence on the effects of cooking duration and kitchen ventilation on these associations in rural areas. Among 29 903 participants from the Henan Rural Cohort, the independent and combined associations of cooking fuel type, cooking duration, and kitchen ventilation with depressive and anxiety symptoms were examined by logistic regression models and restricted cubic spline. The adjusted odds ratios (aORs) and 95% confidence intervals (CIs) of solid fuel use for depressive and anxiety symptoms were 1.237 (1.041, 1.469) and 1.384 (1.153, 1.662), respectively. Increased cooking duration was associated with an increased prevalence of depressive symptoms (aOR: 1.098, 95% CI: 1.033, 1.166) and anxiety symptoms (aOR: 1.074, 95% CI: 1.009, 1.144). Solid fuel use and long-duration cooking associated with increased prevalence of depressive and anxiety symptoms were only observed in individuals without kitchen ventilation. Kitchen ventilation may attenuate the positive associations of solid fuel use and long-duration cooking with the prevalence of depressive and anxiety symptoms, which suggested popularizing clean fuel and promoting kitchen ventilation may be effective strategies to improve mental health related to household air pollution sourced from solid fuel use and long-duration cooking.

Epidemiological evidence relating risk factors to chronic obstructive pulmonary disease in China: A systematic review and meta-analysis

BACKGROUND

Chronic obstructive pulmonary disease (COPD), the most common chronic respiratory disease worldwide, not only leads to the decline of pulmonary function and quality of life consecutively, but also has become a major economic burden on individuals, families, and society in China. The purpose of this meta-analysis was to explore the risk factors for developing COPD in the Chinese population that resides in China and to provide a theoretical basis for the early prevention of COPD.

METHODS

A total of 2457 cross-sectional, case-control, and cohort studies published related to risk factors for COPD in China were searched. Based on the inclusion and exclusion criteria, 20 articles were selected. Stata 11.0 was used for meta-analysis. After merging the data, the pooled effect and 95% confidence intervals (CIs) were calculated to assess the association between risk factors and COPD. Heterogeneity between studies was assessed using I2 and Cochran's Q tests. Begg's test was used to assess publication bias.

RESULTS

Exposure to particulate matter less than 2.5 μm in diameter (PM2.5) (pooled effect = 1.73; 95%CI: 1.16~2.58; P <0.01), smoking history (pooled effect = 2.58; 95%CI: 2.00~3.32; P <0.01), passive smoking history (pooled effect = 1.39; 95%CI: 1.03~1.87; P = 0.03), male sex(pooled effect = 1.70; 95%CI: 1.31~2.22; P <0.01), body mass index (BMI) <18.5 kg/m2 (pooled effect = 1.73; 95%CI: 1.32~2.25; P <0.01), exposure to biomass burning emissions (pooled effect = 1.65; 95%CI: 1.32~2.06; P <0.01), childhood respiratory infections (pooled effect = 3.44; 95%CI: 1.33~8.90; P = 0.01), residence (pooled effect = 1.24; 95%CI: 1.09~1.42; P <0.01), and a family history of respiratory diseases (pooled effect = 2.04; 95%CI: 1.53~2.71; P <0.01) were risk factors for COPD in the Chinese population.

CONCLUSION

Early prevention of COPD could be accomplished by quitting smoking, reducing exposure to air pollutants and biomass burning emissions, maintaining body mass index between 18.5 kg/m2 and 28 kg/m2, protecting children from respiratory infections, adopting active treatments to children with respiratory diseases, and conducting regular screening for those with family history of respiratory diseases.

Associations of solid fuel use and ambient air pollution with estimated 10-year atherosclerotic cardiovascular disease risk

BACKGROUND

Although exposure to ambient air pollution (AAP) increases the risk for arteriosclerotic cardiovascular disease (ASCVD), evidence on the association of solid fuel use with ASCVD and its association modified by ambient air pollution remains limited.

METHODS

A total of 16,779 adults were derived from the Henan Rural Cohort Study. Concentrations of ambient air pollutants (PM₁, PM_2.5, PM₁₀, and NO₂) were estimated by a spatiotemporal model based on satellites data. Solid fuel use was assessed by a self-reported questionnaire. The associations of solid fuel use with high 10-year ASCVD risk and the modified association by exposure to air pollutants were explored using logistic regression models.

RESULTS

There were positive associations of AAP exposure with high 10-year ASCVD risk among individuals with self-cooking. The joint associations between high AAP exposures and solid fuel use with high 10-year ASCVD risk were found. Compared to clean fuel user with low PM_2.5 exposure, the odds ratios (ORs) and 95% confidence intervals (CIs) of high 10-year ASCVD risk was 1.25 (1.09, 1.42) for solid fuel user with low PM_2.5 exposure, 1.93 (1.75, 2.12) for clean fuel user with high PM_2.5 exposure, and 3.08 (2.67, 3.54) for solid fuel user with high PM_2.5 exposure, respectively. Their additive effect on high 10-year ASCVD risk was observed (relative excess risk due to interaction (RERI): 0.90 (95 %CI: 0.50, 1.30), attributable proportion due to interaction (AP): 0.29 (95 %CI: 0.19, 0.40), and synergy index (SI): 1.77 (95 %CI: 1.38, 2.26)).

CONCLUSION

This study showed a synergistic effect of AAP and household air pollution reflected by solid fuel use on high 10-year ASCVD risk, suggesting that reducing solid cooking fuels and controlling air pollution may have a joint effect on public health improvement.

All-Cause Mortality Risk Associated With Solid Fuel Use Among Chinese Elderly People: A National Retrospective Longitudinal Study

Background: The adverse health effects of air pollutants are widely reported, and the elderly are susceptible to toxic environments. This study aimed to evaluate the association between use of solid fuels for cooking and mortality among the elderly. Methods: A total of 5,732 and 3,869 participants from the Chinese Longitudinal Healthy Longevity Survey were enrolled in two (2014 and 2018) and three surveys (2011, 2014, and 2018) of survey. Cooking fuel was divided into clean and solid fuel. Cox proportional hazards models were used to estimate the mortality hazard ratio (HR). Subgroup analyses were performed to assess the potential interaction effect. Results: Among the participants in the 2011-2018 survey, 53% reported using solid fuel. Such group was associated with a 9% increase in mortality risk relative to clean fuel users (HR = 1.09, 95% CI = 1.01-1.18). Among participants in the 2014-2018 survey, 339 reported a switch from solid to clean fuels and they were not at increased mortality risk relative to the 488 people that reported a stable use of clean fuels (HR = 1.14, 95% CI = 0.99-1.31) although the estimated HR was similar to the one for stable solid fuel users (HR = 1.19, 95%CI = 1.04-1.36 n = 509). Interaction and stratified analyses showed that solid fuel use had an impact on mortality in participants who were non-current smokers, had low dietary diversity scores, and were living in areas with high PM2.5 concentrations (>50 μg/m3) and city population below 8 million (P for interaction < 0.05). The association was robust in the three sensitivity analyses. Conclusion: The finding showed a clear association between solid fuel use and mortality among older Chinese, and an even stronger association between risk of mortality and solid fuel use among individuals exposed to high levels of PM2.5.

Increasing mortality caused by chronic obstructive pulmonary disease (COPD) in relation with exposure to ambient fine particulate matters: an analysis in Southeastern China

The objective of this study was to investigate the association between ambient particulate matters (PMs) and chronic obstructive pulmonary disease (COPD) mortality. generalized additive mixed model was employed to investigate the effects of ambient fine and coarse PMs on COPD mortality using 13,066 deaths from 2014 to 2016 among six cities in Zhejiang Province in Southeastern China. The daily average death count due to COPD was 3, varying from 1 to 7 among six cities. The daily 24-h mean concentrations were diverse among cities, from 29.7 to 56.8 μg/m³ for PM_2.5, 16.7 to 30.3 μg/m³ for PM_2.5-10, and 50.3 to 87.1 μg/m³ for PM₁₀, respectively. The analysis showed that daily exposure to PM_2.5 and PM₁₀ was associated with increased mortality due to COPD and that weak effects were observed between PM_2.5-10 and COPD mortality. Our results provided solid evidence that the fine particles in air pollution have stronger functions on adverse health effects other than coarser particles in Southeastern China, which may be considered as a potential clinic target in PM-associated COPD.

Asthma Patients Benefit More Than Chronic Obstructive Pulmonary Disease Patients in the Coronavirus Disease 2019 Pandemic

Background: Coronavirus disease 2019 (COVID-19) has raised many questions about the role of underlying chronic diseases on disease outcomes. However, there is limited information about the effects of COVID-19 on chronic airway diseases. Therefore, we conducted the present study to investigate the impact of COVID-19 on patients with asthma or chronic obstructive pulmonary disease (COPD) and ascertain risk factors for acute exacerbations (AEs). Methods: This single-center observational study was conducted at the Second Xiangya Hospital of Central South University, involving asthma or COPD patients who had been treated with inhaled combination corticosteroids (ICSs), such as budesonide, and one long-acting beta-2-agonist (LABA), such as formoterol, for at least a year before the COVID-19 pandemic. We conducted telephone interviews to collect demographic information and clinical data between January 1, 2019, and December 31, 2020, focusing on respiratory and systemic symptoms, as well as times of exacerbations. Data for asthma and COPD were then compared, and the risk factors for AEs were identified using logistic regression analysis. Results: A total of 251 patients were enrolled, comprising 162 (64.5%) who had asthma and 89 who had COPD, with none having COPD/asthma overlap. Frequency of AEs among asthma patients was significantly lower in 2020 than in 2019 (0.82 ± 3.33 vs. 1.00 ± 3.16; P < 0.05). Moreover, these patients visited the clinic less (0.37 ± 0.93 vs. 0.49 ± 0.94; P < 0.05) and used emergency drugs less (0.01 ± 0.11 vs. 007 ± 0.38; P < 0.05) during the COVID-19 pandemic. In contrast, among COPD patients, there were no significant differences in AE frequency, clinic visits, or emergency drug use. Furthermore, asthma patients visited clinics less frequently during the pandemic than those with COPD. Logistic regression analysis also showed that a history of at least one AE within the last 12 months was associated with increased AE odds for both asthma and COPD during the COVID-19 pandemic (odds ratio: 13.73, 95% CI: 7.04-26.77; P < 0.01). Conclusion: During the COVID-19 pandemic, patients with asthma showed better disease control than before, whereas patients with COPD may not have benefited from the pandemic. For both diseases, at least one AE within the previous 12 months was a risk factor for AEs during the pandemic. Particularly, among asthma patients, the risk factors for AE during the COVID-19 pandemic were urban environment, smoking, and lower asthma control test scores.

Household Air Pollution From Solid Cooking Fuel Combustion and Female Breast Cancer

Background: Women bear a large share of disease burden caused by household air pollution due to their great involvement in domestic activities. Pollutant emissions are believed to vary by exposure patterns such as cooking and space heating. Little is known about the independent effect of solid cooking fuel combustion on breast cancer risk. We aimed to examine the association of indoor coal and wood combustion for cooking with breast cancer risk. Methods: During June 2004-July 2008, participants aged 30-79 from 10 diverse regions across China were enrolled in the China Kadoorie Biobank. Primary cooking fuel use information in up to three residences was self-reported at baseline. Multivariable logistic regression models yielded adjusted odds ratios (ORs) and 95% confidence intervals (CIs). Results: A total of 290,396 female participants aged 30-79 were included in the main analysis. Compared with long-term clean fuel users, the fully adjusted ORs were 2.07 (95%CI: 1.37-3.13) for long-term coal users, 1.12 (95% CI: 0.72-1.76) for long-term wood users, and 0.98 (95% CI: 0.55-1.74) for those who used mixed solid fuels to cook. Those who had switched from solid to clean fuels did not have an excess risk of breast cancer (OR: 0.88, 95%CI 0.71-1.10). Conclusion: Long-term solid fuel combustion for cooking may increase the risk of breast cancer. The strength of association is stronger among coal users than wood users. Targeted interventions are needed to accelerate the access to clean and affordable energy.

Association between household solid fuel use for cooking and sleep disturbance in rural China: findings from the China Kadoorie Biobank data

BACKGROUND

Solid fuel use for cooking is a main source of household air pollution, particularly in rural China. Evidence on the association between household air pollution and sleep quality remains limited. This study aimed to examine the association between household solid fuels used for cooking and sleep disturbance.

METHODS

The data of 283,170 adults from baseline survey of the China Kadoorie Biobank Study were included. Detailed information about exposure to solid fuels used for cooking were collected. Sleep disturbance was indicated as any of the three sleep disorders, including disorders of initiating and maintaining sleep, disorders of early morning awakening, and daytime dysfunction. Logistic regression analysis was used to examine the association between sleep disturbance and level of exposure to household solid fuels used for cooking.

RESULTS

About 18% of participants reported sleep disturbance. Fully adjusted analysis indicated exposure to household solid fuels used for cooking was significantly associated with sleep disturbance. Compared to those with 0-3 years exposure (first tertile) to solid fuels used for cooking, the participants with 3-26 years exposure (second tertile) and >26 years exposure (third tertile) had greater odds of having sleep disturbance at 1.16 (95% CI: 1.12-1.19) and 1.33 (95% CI: 1.29-1.37) times, respectively.

CONCLUSIONS

Use of household solid fuels is associated with prevalence of sleep disturbance; the longer duration of exposure to solid fuels use for cooking, the higher is the prevalence of sleep disturbance. Further study is warranted to examine the underlying mechanisms of the association.

Indoor solid fuel use and incident arthritis among middle-aged and older adults in rural China: A nationwide population-based cohort study

BACKGROUND

Many households in developing countries, including China, rely on the traditional use of solid fuels for cooking and heating. Arthritis is highly prevalent in middle-aged and older adults and is a major cause of disability. However, evidence linking indoor solid fuel use with arthritis is scarce in this age group (≥45 years) in developing countries.

OBJECTIVES

To investigate whether exposure to indoor solid fuel for cooking and heating is associated with arthritis in middle-aged and older adults in rural China.

METHODS

Data for the present study were extracted from the China Health and Retirement Longitudinal Study (CHARLS), a longitudinal national prospective study of adults aged 45 years and older enrolled in 2010 and followed up through 2015. We included 7807 rural participants without arthritis at baseline, of whom 1548 living in a central heating area in winter were included in the heating analysis (taking the Qinling-Huaihe line as the heating boundary). Cox proportional hazards models were used to examine the association between indoor solid fuel use and arthritis, controlling for age, sex, education, marital status, smoking status, drinking status, self-reported socioeconomic status, BMI, sleep time, napping time, independent cooking, hypertension, diabetes, dyslipidemia, heart problems and stroke. We also investigated the effect of switching primary fuels and using solid fuels for both cooking and heating on arthritis risk.

RESULTS

The mean (SD) age of the study participants was 59.2 (10.0) years old, and 48.0% of participants were women. A total of 64.8% and 63.0% of the participants reported primarily using solid fuel for cooking and heating, respectively. Arthritis incidence rates were lower among clean fuel users than solid fuel users. Compared to those using clean fuels, cooking and heating solid fuel users had a higher risk of arthritis, with hazard ratios (HRs) of 1.22 (95% confidence interval (CI): 1.01, 1.49) and 1.76 (95% CI: 1.07, 2.89), respectively. Switching from clean fuels to solid fuels for heating (HR: 3.28, 95% CI: 1.21, 7.91) and using solid fuels for both cooking and heating (HR, 1.71, 95% CI, 1.01-2.79) increased the risk of arthritis.

CONCLUSIONS

Long-term solid fuel use for indoor cooking and heating is associated with an increased risk of arthritis events among adults aged 45 years and older in rural China. The potential benefits of reducing indoor solid fuel use in groups at high risk for arthritis merit further exploration.

A novel living environment exposure matrix of the common organic air pollutants for exposure assessment

Although the most accurate estimations of exposure to organic air pollutants are direct personal measurements, it is prohibitive for large-scale epidemiological studies, both in terms of cost-saving and procedure time. Therefore, indirect exposure assessments offer a potentially feasible approach for estimating population exposures to organic air pollution. The purpose of this study was to develop a novel living environment exposure matrix of the common organic air pollutants, which was used in large-scale epidemiological studies. The common organic air pollutants and a range of potential living environment factors were collected and matched according to the statistics of the Centers for Disease Control and Prevention, the United States Environmental Protection Agency, and the World Health Organization. Paints (dyes), paint removing, and furniture are the most common source of living environment exposure (n = 6). Furthermore, most of the common organic air pollutants are associated with exposure to coal, oil and gasoline burning, smoking, and carpet backing (n ≥ 2). Electricity is considered a clean fuel due to they generate less organic air pollutants compared to other living environment factors in this study. However, whether gas burning is considered as a source of indoor organic air pollutants in large-scale epidemiological studies need to be further investigated. The present study summarizes the living environment exposure matrix of the common organic air pollution, which could be used to estimate exposure to organic air pollutants in large-scale epidemiological studies in the future.

More to Explore: Further Definition of Risk Factors for COPD - Differential Gender Difference, Modest Elevation in PM2.5, and e-Cigarette Use

Chronic obstructive pulmonary disease (COPD) is a severe respiratory disease with high morbidity and mortality, representing the third leading cause of death worldwide. Traditional risk factors for COPD include aging, genetic predisposition, cigarette smoking, exposure to environmental pollutes, occupational exposure, and individual or parental respiratory disease history. In addition, latest studies have revealed novel and emerging risk factors. In this review, differential gender difference as a factor for COPD development at different territories is discussed for the first time. First, women seem to have more COPD, while more women die of COPD or have more severe COPD, in Western societies. This seems different from the impression that COPD dominants in men, which is true in Eastern societies. It might be related to higher rate of cigarette smoking in women in developed countries (i.e., 12.0% of women in United States smoke vs. 2.2% in China). Nonetheless, women in Eastern societies are exposed to more biomass usage. Second, modest elevation in PM2.5 levels at >∼21.4-32.7 μg/m3, previously considered "cleaner air," is associated with incidence of COPD, indicating that more stringent goals should be set for the reduction of PM2.5 levels to prevent COPD development. Last but not least, e-cigarette use, which has become an epidemic especially among adolescents as officially declared by the United States government, has severe adverse effects that may cause development of COPD early in life. Built upon an overview of the established risk factors for COPD primarily focusing on cigarette smoking and environmental pollutions, the present review further discusses novel concepts, mechanisms, and solutions evolved around the emerging risk factors for COPD discussed above, understanding of which would likely enable better intervention of this devastating disease.

Sex difference in the association between solid fuel use and cognitive function in rural China

BACKGROUND

Whether indoor air pollution from solid fuel use is associated with cognitive function remains unclear.

OBJECTIVE

This study aims to examine the association of solid fuel use with the risk of cognitive impairment in males and females.

METHODS

The data was from the China Health and Retirement Longitudinal Study (CHARLS). Self-reported heating and cooking fuel were categorized as clean fuel (solar, liquefied gas, natural gas, or electricity) and solid fuel (coal, biomass charcoal, wood, or straw). Cognitive function, including orientation and attention, episodic memory, and visuospatial abilities, was assessed using standardized questionnaires.

RESULTS

A total of 7824 individuals were included in our study (aged 57.0 ± 9.3, 46.2% female), with 47.0% and 76.0% used solid fuel for cooking and heating, respectively. There was an interaction between sex and solid fuel use for cooking (P=0.008) for the progress of cognitive impairment. Solid fuel use for cooking was associated with a larger decrease in cognitive function score in females (β=-0.832; 95% CI: -1.043, -0.622; P < 0.001) than in males (β=-0.487; 95% CI: -0.671, -0.302; P < 0.001). The sex difference remained with further adjustment of covariates (β=-0.321; 95% CI: -0.503, -0.138; P=0.001 for males; β=-0.534; 95% CI: -0.745, -0.324; P < 0.001 for females). For heating, the interaction between sex and solid fuel was not statistically significant (P=0.156). After controlling for the covariates, solid fuel use for heating was inversely associated with a 0.321 unit of decrease of cognitive function score (β=-0.321; 95% CI: -0.652, 0.009; P=0.057) in males, and a 0.598 unit of decrease of cognitive function (β=-0.598; 95% CI: -0.978, -0.218; P=0.002) in females.

CONCLUSION

In conclusion, solid fuel use for cooking and heating was significantly associated with a higher risk of cognitive impairment. Furthermore, for the first time, we found that the effect of solid fuel use on cognitive function in females was greater than in males.

Regional Policies Targeting Residential Solid Fuel and Agricultural Emissions Can Improve Air Quality and Public Health in the Greater Bay Area and Across China

Air pollution exposure is a leading public health problem in China. The majority of the total air pollution disease burden is from fine particulate matter (PM2.5) exposure, with smaller contributions from ozone (O3) exposure. Recent emission reductions have reduced PM2.5 exposure. However, levels of exposure and the associated risk remain high, some pollutant emissions have increased, and some sectors lack effective emission control measures. We quantified the potential impacts of relevant policy scenarios on ambient air quality and public health across China. We show that PM2.5 exposure inside the Greater Bay Area (GBA) is strongly controlled by emissions outside the GBA. We find that reductions in residential solid fuel use and agricultural fertilizer emissions result in the greatest reductions in PM2.5 exposure and the largest health benefits. A 50% transition from residential solid fuel use to liquefied petroleum gas outside the GBA reduced PM2.5 exposure by 15% in China and 3% within the GBA, and avoided 191,400 premature deaths each year across China. Reducing agricultural fertilizer emissions of ammonia by 30% outside the GBA reduced PM2.5 exposure by 4% in China and 3% in the GBA, avoiding 56,500 annual premature deaths across China. Our simulations suggest that reducing residential solid fuel or industrial emissions will reduce both PM2.5 and O3 exposure, whereas other policies may increase O3 exposure. Improving particulate air quality inside the GBA will require consideration of residential solid fuel and agricultural sectors, which currently lack targeted policies, and regional cooperation both inside and outside the GBA.

Nitrogen dioxide exposures from LPG stoves in a cleaner-cooking intervention trial

BACKGROUND

Liquefied petroleum gas (LPG) stoves have been promoted in low- and middle-income countries (LMICs) as a clean energy alternative to biomass burning cookstoves.

OBJECTIVE

We sought to characterize kitchen area concentrations and personal exposures to nitrogen dioxide (NO₂) within a randomized controlled trial in the Peruvian Andes. The intervention included the provision of an LPG stove and continuous fuel distribution with behavioral messaging to maximize compliance.

METHODS

We measured 48-hour kitchen area NO₂ concentrations at high temporal resolution in homes of 50 intervention participants and 50 control participants longitudinally within a biomass-to-LPG intervention trial. We also collected 48-hour mean personal exposures to NO₂ among a subsample of 16 intervention and 9 control participants. We monitored LPG and biomass stove use continuously throughout the trial.

RESULTS

In 367 post-intervention 24-hour kitchen area samples of 96 participants' homes, geometric mean (GM) highest hourly NO₂ concentration was 138 ppb (geometric standard deviation [GSD] 2.1) in the LPG intervention group and 450 ppb (GSD 3.1) in the biomass control group. Post-intervention 24-hour mean NO₂ concentrations were a GM of 43 ppb (GSD 1.7) in the intervention group and 77 ppb (GSD 2.0) in the control group. Kitchen area NO₂ concentrations exceeded the WHO indoor hourly guideline an average of 1.3 h per day among LPG intervention participants. GM 48-hour personal exposure to NO₂ was 5 ppb (GSD 2.4) among 35 48-hour samples of 16 participants in the intervention group and 16 ppb (GSD 2.3) among 21 samples of 9 participants in the control group.

DISCUSSION

In a biomass-to-LPG intervention trial in Peru, kitchen area NO₂ concentrations were substantially lower within the LPG intervention group compared to the biomass-using control group. However, within the LPG intervention group, 69% of 24-hour kitchen area samples exceeded WHO indoor annual guidelines and 47% of samples exceeded WHO indoor hourly guidelines. Forty-eight-hour NO₂ personal exposure was below WHO indoor annual guidelines for most participants in the LPG intervention group, and we did not measure personal exposure at high temporal resolution to assess exposure to cooking-related indoor concentration peaks. Further research is warranted to understand the potential health risks of LPG-related NO₂ emissions and inform current campaigns which promote LPG as a clean-cooking option.

Solid fuel use for heating and risks of breast and cervical cancer mortality in China

BACKGROUND

Carcinogens released from indoor burning of solid fuels are believed to enter the bloodstream and to be metabolized in breast and cervical tissues. Little evidence exists about the relationship of solid fuel use from heating with breast and cervical cancer.

OBJECTIVES

To examine the association of solid heating fuel use with breast and cervical cancer mortality.

METHODS

This study included female participants aged 30-79 years who were enrolled in the China Kadoorie Biobank during 2004-2008 from 10 diverse regions across China. During a 10.2-year median follow-up, 177 breast cancer deaths and 113 cervical cancer deaths were documented. Multivariable Cox regression models yielded adjusted hazard ratios (HRs) for the associations of self-reported long-term heating fuel exposure with two cancer deaths. Stratified analyses were used to assess effect modification.

RESULTS

We included 236,116 participants for breast cancer analyses and 228,795 for cervical cancer analyses. Compared with non-solid fuel use, the fully adjusted HRs of cervical cancer deaths were 1.75 (0.91-3.38) for wood use, 2.23 (1.09-4.59) for mixed fuel (coal and wood) use. No evident relationship was observed for breast cancer deaths. Cervical cancer risk increased with the duration of solid fuel use (P for trend = 0.041). Elevated cervical cancer risk was observed in post-menopausal women (HR 2.01, 1.01-4.03), not in pre-menopausal women (HR 0.77, 0.56-2.31) (P for heterogeneity = 0.004); and in those aged ≥50 years (HR 2.56, 1.17-5.86), not in those aged < 50 years (HR 0.69, 0.26-1.84) (P < 0.001).

CONCLUSION

Indoor solid fuel combustion for heating may be associated with a higher risk for cervical cancer death, but not for breast cancer. The strength of the association increased with the duration of exposure and was modified by age and menopause status.

Nitrogen dioxide exposures from biomass cookstoves in the Peruvian Andes

BACKGROUND

Household air pollution from biomass cookstoves is a major contributor to global morbidity and mortality, yet little is known about exposures to nitrogen dioxide (NO₂ ).

OBJECTIVE

To characterize NO₂ kitchen area concentrations and personal exposures among women with biomass cookstoves in the Peruvian Andes.

METHODS

We measured kitchen area NO₂ concentrations at high-temporal resolution in 100 homes in the Peruvian Andes. We assessed personal exposure to NO₂ in a subsample of 22 women using passive samplers.

RESULTS

Among 97 participants, the geometric mean (GM) highest hourly average NO₂ concentration was 723 ppb (geometric standard deviation (GSD) 2.6) and the GM 24-hour average concentration was 96 ppb (GSD 2.6), 4.4 and 2.9 times greater than WHO indoor hourly (163 ppb) and annual (33 ppb) guidelines, respectively. Compared to the direct-reading instruments, we found similar kitchen area concentrations with 48-hour passive sampler measurements (GM 108 ppb, GSD 3.8). Twenty-seven percent of women had 48-hour mean personal exposures above WHO annual guidelines (GM 18 ppb, GSD 2.3). In univariate analyses, we found that roof, wall, and floor type, as well as higher SES, was associated with lower 24-hour kitchen area NO₂ concentrations.

PRACTICAL IMPLICATIONS

Kitchen area concentrations and personal exposures to NO₂ from biomass cookstoves in the Peruvian Andes far exceed WHO guidelines. More research is warranted to understand the role of this understudied household air pollutant on morbidity and mortality and to inform cleaner-cooking interventions for public health.

Cooking fuels and risk of all-cause and cardiopulmonary mortality in urban China: a prospective cohort study

BACKGROUND

Cooking practice has transitioned from use of solid fuels to use of clean fuels, with addition of better ventilation facilities. However, the change in mortality risk associated with such a transition remains unclear.

METHODS

The China Kadoorie Biobank (CKB) Study enrolled participants (aged 30-79 years) from ten areas across China; we chose to study participants from five urban areas where transition from use of solid fuels to clean fuels for cooking was prevalent. Participants who reported regular cooking (weekly or more frequently) at baseline were categorised as persistent clean fuel users, previous solid fuel users, or persistent solid fuel users, according to self-reported fuel use histories. All-cause and cardiopulmonary mortality were identified through linkage to China's Disease Surveillance Point system and local mortality records.

FINDINGS

Between June 24, 2004, and July 15, 2008, 226 186 participants living in five urban areas of China were enrolled in the CKB Study. Among 171 677 participants who reported cooking regularly (weekly or more frequently), 75 785 (44%) were persistent clean fuel users, 80 511 (47%) were previous solid fuel users, and 15 381 (9%) were persistent solid fuel users. During a mean of 9·8 (SD 1·7) years of follow-up, 10 831 deaths were documented, including 3819 cardiovascular deaths and 761 respiratory deaths. Compared with persistent clean fuel users, persistent solid fuel users had significantly higher risks of all-cause mortality (hazard ratio [HR] 1·19, 95% CI 1·10-1·28), cardiovascular mortality (1·24, 1·10-1·39), and respiratory mortality (1·43, 1·10-1·85). The excess risk of all-cause and cardiopulmonary mortality fell by more than 60% in 5 years after cessation of solid fuel use and continued to decrease afterwards. Use of ventilation was associated with lower all-cause mortality risk, even among persistent clean fuel users (HR 0·78, 0·69-0·89).

INTERPRETATION

Solid fuel use for cooking is associated with a higher risk of mortality, and cessation of solid fuel use cuts excess mortality risks swiftly and substantially within 5 years. Ventilation use also lowers the risk of mortality, even among people who persistently use clean fuels. It is of prime importance for both policy makers and the public to accelerate the transition from solid fuels to clean fuels and promote efficient ventilation to minimise further adverse health effects.

FUNDING

National Natural Science Foundation of China, Wellcome Trust, and Kadoorie Charitable Foundation.

Association of solid fuel use with risk of stunting in children living in China

Stunting adversely affects physical and mental outcomes of children. It has not been examined whether household air pollution from solid fuel combustion is a risk factor for stunting in children. In a total of 41,439 children aged 6-17 across China, height was measured using a unified protocol. Multivariable linear regression models and logistic regression models were used to assess the associations of solid fuel use for cooking/heating with stunting in children. Adjusted for covariates, cooking/heating with solid fuel was significantly associated with a lower z-score for height for age and sex (β = -0.21 [-0.32 to -0.09] and -0.17 [-0.31 to -0.03], respectively) and an increased risk of stunting with an estimated ORs of 1.34 [1.07~1.68] and 1.37 [1.02~1.83], respectively. The risk of stunting associated with solid fuel use was statistically significant in high-age children. And the effect was greater on girls than on boys, though the difference was not statistically significant. Our study suggested that Chinese children living in households using solid fuel had a significantly higher risk of stunting than those living in households using cleaner fuel.