Body mass index and mortality in China: a 15-year prospective study of 220 000 men

Association Between Body Mass Index, Obesity, and Clinical Outcomes Following Coronary Artery Bypass Grafting in Brazil: An Analysis of One Year of Follow-up of BYPASS Registry Patients

OBJECTIVE

To investigate the association between body mass index (BMI), obesity, clinical outcomes, and mortality following coronary artery bypass grafting (CABG) in Brazil using a large sample with one year of follow-up from the Brazilian Registry of Cardiovascular Surgeries in Adults (or BYPASS) Registry database.

METHODS

A multicenter cohort-study enrolled 2,589 patients submitted to isolated CABG and divided them into normal weight (BMI 20.0-24.9 kg/m2), overweight (BMI 25.0-29.9 kg/m2), and obesity (BMI > 30.0 kg/m2) groups. Inpatient postoperative outcomes included the most frequently described complications and events. Collected post-discharge outcomes included rehospitalization and mortality rates within 30 days, six months, and one year of follow-up.

RESULTS

Sternal wound infections (SWI) rate was higher in obese compared to normal-weight patients (relative risk [RR]=5.89, 95% confidence interval [CI]=2.37-17.82; P=0.001). Rehospitalization rates in six months after discharge were higher in obesity and overweight groups than in normal weight group (χ=6.03, P=0.049); obese patients presented a 2.2-fold increase in the risk for rehospitalization within six months compared to normal-weight patients (RR=2.16, 95% CI=1.17-4.09; P=0.045). Postoperative complications and mortality rates did not differ among groups during time periods.

CONCLUSION

Obesity increased the risk for SWI, leading to higher rehospitalization rates and need for surgical interventions within six months following CABG. Age, female sex, and diabetes were associated with a higher risk of mortality. The obesity paradox remains controversial since BMI may not be sufficient to assess postoperative risk in light of more complex and dynamic evaluations of body composition and physical fitness.

Body Mass Index and All-Cause Mortality in Elderly Patients with Percutaneous Coronary Intervention: A Meta-Analysis

INTRODUCTION

The "obesity paradox" in elderly patients suffering from percutaneous coronary intervention (PCI) remains a source of controversy. The present meta-analysis focused on exploring the real existence of "obesity paradox" in these patients.

METHODS

As of November 2022, PubMed, Cochrane, and Embase databases were comprehensively searched to identify articles reporting all-cause mortality according to diverse body mass index (BMI) categories after PCI among the old cases developing coronary artery disease (CAD). Summary estimates of relative risks (RRs) were assigned to four BMI groups, including underweight, normal weight, overweight, and obesity groups.

RESULTS

There were altogether nine articles involving 25,798 cases selected for further analysis. Relative to normal weight group, overweight and obesity groups had decreased all-cause mortality (RR: 0.86, 95% CI: 0.77-0.95 for overweight group; RR: 0.57, 95% CI: 0.40-0.80 for obesity group), while underweight group had elevated all-cause mortality (RR: 1.52, 95% CI: 1.01-2.29).

CONCLUSION

Our study revealed an "obesity paradox" relation of BMI with all-cause mortality in elderly cases receiving PCI. In comparison with normal weight group, overweight and obesity groups had decreased all-cause mortality, while underweight group had increased all-cause mortality.

Intragastric injection of botulinum toxin in the treatment of obesity: a single-center study

Background

In recent years, various novel surgical and non-surgical therapeutic options have been developed for treating obesity. Due to its disputed success, intragastric botulinum toxin A (BTX-A) injection is still being debated.

Objectives

We aim to contribute to this controversial issue in the literature by sharing our center's findings regarding intragastric BTX-A injections in the treatment of obesity.

Design

Patients with a body mass index (BMI) of greater than 25 kg/m2 and at least one obesity-related complication, or a BMI of greater than 30 kg/m2 without complications, were eligible for the study if they were between the ages of 18 and 65.

Methods

Following the same procedure, two endoscopists administered BTX-A to all patients. All patients were evaluated for obesity by measuring their lipid profile, hormone profile, and insulin resistance level before treatment.

Results

In our study on 82 patients, we saw a significant mean weight loss (-9.2 kg, p < 0.001) in the second month, and there was no additional mean weight loss in the sixth month of follow-up. In addition, this result seems to be independent of the patient's insulin resistance. We did not see any serious side effects in any of the patients.

Conclusion

Although the use of intragastric injection of BTX-A in the treatment of obesity is a controversial issue, we showed in our study that it causes significant weight loss. Further studies are needed on this subject, as it can be a safe method when the ideal dose and application site are combined with appropriate patient selection.

Overall and abdominal obesity and risks of all-cause and cause-specific mortality in Korean adults: a pooled analysis of three population-based prospective cohorts

BACKGROUND

Studies found a J-shaped association between body mass index (BMI) and mortality. However, it is unclear whether the association is driven by biases, particularly confounding by fat-free mass.

METHODS

We conducted an individual-level pooled analysis of three cohorts of Korean adults (aged ≥ 40 years; n = 153 248). Mortality was followed up through December 2019. Anthropometric data were directly measured at baseline. Fat and fat-free mass were predicted using validated prediction models. Using Cox proportional hazards models, we estimated the associations of BMI and waist circumference (WC) with all-cause and cause-specific mortality. To account for biases, we excluded participants aged ≥ 70 years, deaths that occurred within 5 years of follow-up and ever smokers, and adjusted for fat-free mass index (FFMI).

RESULTS

During the follow-up of up to 18 years, 6061 deaths were identified. We observed J-shaped association of BMI (nadir at 22-26) and monotonically positive association of WC with all-cause, cardiovascular, and cancer mortality among Korean adults without a history of cancer or cardiovascular disease. In the BMI analysis, excluding ever smokers and adjusting for FFMI attenuated the excess mortality in underweight participants and transformed the J-shaped association into a monotonically positive shape, suggesting an increased mortality at BMI > 22.0. Excluding participants aged ≥ 70 years and deaths that occurred within 5 years of follow-up did not change the results. In the WC analysis, the monotonic positive associations did not change after the control. Similar results were observed among participants with a history of cancer or cardiovascular disease.

CONCLUSIONS

Our data suggest that both overall and abdominal body fat are associated with increased mortality in Korean adults.

Associations of types of grains and lifestyle with all-cause mortality among Chinese adults aged 65 years or older: a prospective cohort study

BACKGROUND

Little is known on the association of types of grains with mortality and the moderating effect of lifestyle on this association. This study aims to evaluate the single or joint associations of types of grains and lifestyle with all-cause mortality among Chinese older adults.

METHODS

Data were derived from the Chinese Longitudinal Healthy Longevity Survey (CLHLS) from 1998 to 2018. Subjects aged ≥ 65 years were eligible. The types of grains included wheat, total rice, and coarse cereals. Lifestyle was derived using smoking, alcohol consumption, physical activity, and dietary pattern. All-cause mortality was the primary outcome.

RESULTS

This study included 30275 participants with a mean age 87 ± 11 years and documented 19261 deaths during a mean follow-up of 4.8 years. Compared to wheat, in those with healthy and intermediate lifestyle, total rice was associated with a 13% (HR: 0.87, 95% CI 0.80, 0.93) and 6% (HR: 0.94, 95% CI 0.90, 1.00) lower risk of mortality, respectively, and coarse cereals were associated with a 14% (HR: 0.86, 95% CI 0.74, 1.00) and 12% (HR: 0.88, 95% CI 0.79, 0.97) lower risk of mortality, respectively. Meanwhile, an increase per SD in intakes of wheat and coarse cereals was associated with a 10% (HR: 1.10, 95% CI 1.03, 1.18) and 25% (HR: 1.25, 95% CI 1.08, 1.44) higher mortality rate in those with healthy lifestyle, and a 13% (HR: 1.13, 95% CI 1.08, 1.19) and 29% (HR: 1.29, 95% CI 1.17, 1.44) higher mortality in females but not males. In addition, a U-shaped association of intake of total grains with all- cause mortality was observed (P for non-linearity = 0.002), and a J-shaped association of intake of total rice with all- cause mortality was observed (P for non-linearity = 0.003).

CONCLUSIONS

Specific types of grains and lifestyle were separately or jointly associated with all-cause mortality. Compared to wheat, total rice and coarse cereals were advanced grains for participants with a relatively healthy lifestyle. Intake of total rice was related to all-cause mortality in a dose-response manner. Therefore, a combination of intermediate intake of total rice and healthy lifestyle should be encouraged in older adults.

Association Between Fat Mass to Lean Body Mass Ratio and All-Cause Mortality Among Middle-Aged and Elderly Cancer Patients Without Obesity: A Multi-Center Observational Study in China

Objective

We aimed to investigate the association between fat mass to lean body mass ratio (RFL), percentage of body fat (PBF), and fat mass (FM) with mortality among middle-aged and elderly cancer patients without obesity.

Methods

This prospective hospital-based cohort study comprised 3,201 patients with stage I to IV cancer aged 40 years or above (mean age: 58 years for female patients and 61 years for male patients; mean length of follow-up was 1.67 years; the maximal follow-up length was 6.42 years). FM and PBF were measured by bioelectrical impedance analysis (BIA). Cox proportional hazard models were used, and adjusted hazard ratios (HRs) were estimated.

Results

We revealed a significant association between RFL and all-cause mortality among men aged ≥60 years after adjusting for confounders. Compared with those in the lowest tertile of RFL, elderly men in the medium and highest tertile had a 35 and 34% lower hazard of death from any cause, respectively. After additionally adjusted for C-reaction protein (CRP), HRs of medium and high tertile of RFL became short of statistical significance [medium tertile: adjusted HRs (95% CI) = 0.74 (0.46, 1.20); highest tertile: adjusted HRs (95% CI) = 0.84 (0.53, 1.33)]. Among elderly women, RFL was significantly related to all-cause mortality only when the additional adjustment for CRP [medium tertile: adjusted HRs (95% CI) = 2.08 (1.08, 4.01); highest tertile: adjusted HRs (95% CI) = 0.90 (0.45, 1.81)]. No significant association between RFL and all-cause mortality was observed among female participants or male participants aged less than 60 years.

Conclusion

Our findings showed a significant non-linear association between RFL and all-cause mortality, which was observed only in elderly men, and might be attenuated by their inflammation state.

Hypertension modifies the associations of body mass index and waist circumference with all-cause mortality among older Chinese: a retrospective cohort study

Background

The effect of baseline hypertension status on the BMI–mortality association is still unclear. We aimed to explore the relationships of body mass index (BMI) and waist circumference (WC) with all-cause mortality among older hypertensive and normotensive Chinese individuals.

Methods

This retrospective cohort study was conducted in Xinzheng, Henan Province, Central China. The data came from the residents’ electronic health records of the Xinzheng Hospital Information System. A total of 77,295 participants (41,357 hypertensive participants and 35,938 normotensive participants) aged ≥ 60 years were included from January 2011 to November 2019. Cox proportional hazard regression model was used to examine the relationships.

Results

During a mean follow-up of 5.3 years, 10,755 deaths were identified (6,377 in hypertensive participants and 4,378 in normotensive participants). In adjusted models, compared with a BMI of 18.5–24 kg/m², the hazard ratios (HRs) and corresponding 95% confidence intervals (CIs) of BMI < 18.5, 24–28 and ≥ 28 kg/m² for mortality in hypertensive participants were 1.074 (0.927–1.244), 0.881 (0.834–0.931) and 0.856 (0.790–0.929), respectively, and 1.444 (1.267–1.646), 0.884 (0.822–0.949) and 0.912 (0.792–1.051), respectively, in normotensive participants. Compared with normal waist circumference, the adjusted HRs and 95% CIs of central obesity for mortality were 0.880 (0.832–0.931) in hypertensive participants and 0.918 (0.846–0.996) in normotensive participants. A sensitivity analysis showed similar associations for both hypertensive and normotensive participants.

Conclusion

Low BMI and WC were associated with a higher risk of all-cause mortality regardless of hypertension status in older Chinese individuals. The lowest risk of death associated with BMI was in the overweight group in normotensive participants and in the obesity group in hypertensive participants.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12877-022-03057-9.

Association Between Body Mass Index and All-Cause Mortality in a Prospective Cohort of Southern Chinese Adults Without Morbid Obesity

Objective: This prospective study examined the relationship between body mass index (BMI) and all-cause mortality in Chinese adults without morbid obesity.

Methods: We prospectively examined the relationship between BMI and all-cause mortality in 12,608 Southern Chinese adults with age ≥35 years who participated in the National Key R&D Program from 2013–2014 to 2019–2020. Cox proportional hazards models were used to examine the association between BMI and all-cause mortality.

Results: The prevalence of being underweight, normal weight, overweight and having moderate obesity was 7.36%, 55.83%, 28.51% and 8.31%, respectively. A total of 683 (5.65%) deaths occurred during a median follow-up period of 5.61 years. The Cox proportional hazards models indicated that a continuous BMI level was negatively associated with all-cause mortality [adjusted-hazard ratio (HR) per 1 kg/m² increase: 0.96, 95% CI 0.93 to 0.98, p < 0.001]. Furthermore, the HRs of all-cause mortality in the underweight, overweight and moderate obesity groups were 1.31 (1.05, 1.64), 0.89 (0.73, 1.08) and 0.64 (0.44, 0.92), respectively in the confounder model relative to the normal weight group. Survival analysis further confirmed this inverse association of the four BMI categories with mortality.

Conclusion: BMI was negatively associated with all-cause mortality in southern Chinese adults without morbid obesity. Compared to the normal weight category, adults in the moderate obesity category had lower all-cause mortality, whereas being underweight was associated with increased all-cause mortality.

Risk factors for incident cardiovascular events among adults in low- and middle-income countries: A systematic review and meta-analysis of prospective cohort studies

The relative contributions of risk factors for cardiovascular events at a population level has received little attention in low- and middle-income countries (LMICs). We estimated the population attributable fraction (PAF) of risk factors associated with incident cardiovascular events in LMICs. We searched six databases for relevant articles, supplemented with a manual search of reference lists. Articles included in the meta-analyses were those based on prospective community-based cohorts and incorporating adjusted hazard ratios (HR) or relative risks with 95% confidence intervals (95% CI) for associations between risk factors and a composite cardiovascular and/or stroke endpoint. Pooled HRs and 95% CI were calculated using the random effects model. We assessed heterogeneity using the I² test and study quality using the Newcastle-Ottawa Scale. We calculated the PAF of each associated risk factor. The protocol was registered in PROSPERO (CRD42019122741). We identified 18 cohorts from LMICs with 1,125,846 participants, 77,045 composite cardiovascular events and 42,216 strokes. Substantial proportions of incident cardiovascular events were attributable to hypertension (HR [95% CI], 2.23 [2.01-2.48], PAF = 28%); current smoking (1.44 [1.31-1.58], PAF = 10%); and diabetes mellitus (1.93 [1.67-2.23], PAF = 8%). Other risk factors identified included number of children, depression, bone mineral density, and air pollution. A substantial proportion of incident cardiovascular events were linked to traditional metabolic and behavioural modifiable risk factors. However, other novel risk factors also appear to contribute. Targeting of these established and novel risk factors has the potential to reduce the burden of CVD in LMICs.

Association between body mass index and oesophageal cancer mortality: a pooled analysis of prospective cohort studies with >800 000 individuals in the Asia Cohort Consortium

BACKGROUND

The association between body mass index (BMI) and oesophageal cancer (OC) has been consistently negative among Asians, whereas different associations based on histological OC subtypes have been observed in Europeans and North Americans. We examined the association between BMI and OC mortality in the Asia Cohort Consortium.

METHODS

We performed a pooled analysis to evaluate the association between BMI and OC mortality among 842 630 Asians from 18 cohort studies. Cox regression models were used to estimate hazard ratios (HRs) and 95% CIs.

RESULTS

A wide J-shaped association between BMI and overall OC mortality was observed. The OC mortality risk was increased for underweight (BMI <18.5 kg/m2: HR = 2.20, 95% CI 1.80-2.70) and extreme obesity (BMI ≥35 kg/m2: HR = 4.38, 95% CI 2.25-8.52) relative to the reference BMI (23-25 kg/m2). This association pattern was confirmed by several alternative analyses based on OC incidence and meta-analysis. A similar wide J-shaped association was observed in oesophageal squamous cell carcinoma (OSCC). Smoking and alcohol synergistically increased the OC mortality risk in underweight participants (HR = 6.96, 95% CI 4.54-10.67) relative to that in reference BMI participants not exposed to smoking and alcohol.

CONCLUSION

Extreme obesity and being underweight were associated with an OC mortality risk among Asians. OC mortality and BMI formed a wide J-shaped association mirrored by OSCC mortality. Although the effect of BMI on OSCC and oesophageal adenocarcinoma mortality can be different in Asians, further research based on a large case-control study is recommended.

Association between dairy consumption and ischemic heart disease among Chinese adults: a prospective study in Qingdao

BACKGROUND

Previous studies linking dairy consumption with ischemic heart disease (IHD) are almost from western countries, with little from China. The present study was to explore the relationship between dairy consumption and IHD among Chinese adults.

METHODS

The data for the present study was from the prospective cohort study of China Kadoorie Biobank in Qingdao, a total of 33,355 participants in the present study. An interviewer-administered laptop-based questionnaire was used to collect information on the consumption frequency of dairy, incident IHD cases were identified through Disease Surveillance Point System and the new national health insurance databases. Cox regression analyses were performed to estimate adjusted hazard ratios (HRs) and confidence interval for the relationship between the incidence of IHD and dairy consumption.

RESULTS

The baseline survey reported that 32.4% of males and 34.6% of females consumed dairy regularly (i.e. ≥ 4 days/week). Over an average of 9.2 years follow-up, 2712 new-onset IHD were documented. Compared with participants who never or rarely consume dairy, the HR of consumed dairy regularly was 0.85(0.73-0.98) for males (P < 0.05), while no significant benefits were identified for females.

CONCLUSIONS

Regular dairy consumption had an inverse association to the onset of IHD among males, with no similar findings for females.

The effect of BMI on COVID-19 outcomes among older patients in South Korea: a nationwide retrospective cohort study

Background: The coronavirus disease 2019 (COVID-19) pandemic has caused deaths and shortages in medical resources worldwide, making the prediction of patient prognosis and the identification of risk factors very important. Increasing age is already known as one of the main risk factors for poor outcomes, but the effect of body mass index (BMI) on COVID-19 outcomes in older patients has not yet been investigated. Aim: We aimed to determine the effect of BMI on the severity and mortality of COVID-19 among older patients in South Korea. Methods: Data from 1272 COVID-19 patients (≥60 years old) were collected by the Korea Centers for Disease Control and Prevention. The odds ratios (ORs) of severe infection and death in the BMI groups were analyzed by logistic regression adjusted for covariates.Results: The underweight group (BMI<18.5 kg/m2) had a higher OR for death (adjusted OR = 2.23, 95% confidence interval [95% CI] = 1.06-4.52) than the normal weight group (BMI, 18.5-22.9 kg/m2). Overweight (BMI, 23.0-24.9 kg/m2) was associated with lower risks of both severe infection (adjusted OR = 0.55, 95% CI = 0.31-0.94) and death (adjusted OR = 0.50, 95% CI = 0.27-0.91). Conclusions: Underweight was associated with an increased risk of death, and overweight was related to lower risks of severe infection and death in older COVID-19 patients in Korea. However, this study was limited by the lack of availability of some information, including smoking status.KEY MESSAGESUnderweight is an independent risk factor of death in older COVID-19 patients.Overweight patients have a lower risk of death and severe infection than normal-weight patients.

Epidemiology and determinants of obesity in China

Obesity has become a major public health issue in China. Overweight and obesity have increased rapidly in the past four decades, and the latest national prevalence estimates for 2015-19, based on Chinese criteria, were 6·8% for overweight and 3·6% for obesity in children younger than 6 years, 11·1% for overweight and 7·9% for obesity in children and adolescents aged 6-17 years, and 34·3% for overweight and 16·4% for obesity in adults (≥18 years). Prevalence differed by sex, age group, and geographical location, but was substantial in all subpopulations. Strong evidence from prospective cohort studies has linked overweight and obesity to increased risks of major non-communicable diseases and premature mortality in Chinese populations. The growing burden of overweight and obesity could be driven by economic developments, sociocultural norms, and policies that have shaped individual-level risk factors for obesity through urbanisation, urban planning and built environments, and food systems and environments. Substantial changes in dietary patterns have occurred in China, with increased consumption of animal-source foods, refined grains, and highly processed, high-sugar, and high-fat foods, while physical activity levels in all major domains have decreased with increasing sedentary behaviours. The effects of dietary factors and physical inactivity intersect with other individual-level risk factors such as genetic susceptibility, psychosocial factors, obesogens, and in-utero and early-life exposures. In view of the scarcity of research around the individual and collective roles of these upstream and downstream factors, multidisciplinary and transdisciplinary studies are urgently needed to identify systemic approaches that target both the population-level determinants and individual-level risk factors for obesity in China.

Pharmacoeconomics of obesity in China: a scoping review

Background: With the growing rate of obesity and associated chronic conditions in China, there is a need to assess the health and economic burdens of obesity and examine the effectiveness of pharmaceutical, medical, and comprehensive weight-loss interventions.Areas covered: This article reviewed publications retrieved from PubMed and Google Scholar during 2010-2020 on pharmacoeconomic studies related to overweight and obesity in China. We identified five cost-of-illness studies and four cost-effectiveness analyses of weight-loss interventions, including bariatric surgeries and a comprehensive intervention program.Expert opinion: There is a lack of pharmacoeconomic analyses of obesity in China. Existing studies have often taken the health system perspective without accounting for productivity loss. Cohort studies and studies based on electronic health records or claims data are needed to provide the epidemiologic parameters required for homegrown economic evaluations of the health and economic burdens of obesity in China, as well as the cost-effectiveness of interventions to reduce obesity and its sequela.

The Relationship between Body Mass Index and Incident Diabetes Mellitus in Chinese Aged Population: A Cohort Study

OBJECTIVES

Previous studies reported that overweight older adults had a lower mortality after cardiovascular diseases attack, indicating being thinner might not always be better. However, there is an ongoing debate about what is the optimal range of body mass index (BMI) for the aged population. We aimed to evaluate the value of BMI for the prediction of incident diabetes mellitus (DM) in the Chinese elderly population.

METHODS

A total number of 6,911 Chinese elderly people (4,110 men and 2,801 women, aged 71 ± 6.0 years) were included in this cohort study. BMI was measured at baseline (Jan 1, 2014, to Dec 31, 2014). All the participants were further classified into six groups: <18.5 kg/m², 18.5 to <22.5 kg/m², 22.5 to <25.0 kg/m², 25.0 to <27.5 kg/m², 27.5 to <30.0 kg/m², and ≥30.0 kg/m². Fasting blood glucose (FBG) and glycated hemoglobin A1c (HbA1c) were annually measured during follow-up (Jan 1, 2015-May 31, 2019). DM was confirmed if either FBG ≥ 7.0 mmol/L or HbA1c ≥ 6.5%. We used the Cox proportional hazard regression model to evaluate the association between BMI and the prediction of incident DM.

RESULTS

Comparing individuals with a BMI range of 18.5 to <22.5 kg/m² (reference), the hazard ratio for incident DM was 2.13 (95% CI: 1.54~2.95), 2.14 (95% CI: 1.53~3.00), 3.17 (95% CI: 2.19~4.59), 3.15 (95% CI: 1.94~5.09), and 3.14 (95% CI: 1.94~5.09) for the group with a BMI range of 22.5 to <25.0 kg/m², 25.0 to <27.5 kg/m², 27.5 to <30.0 kg/m², and ≥30.0 kg/m² after adjusting for baseline age, sex, blood pressure, lipid profiles, and eGFR (P trend < 0.001), after adjusting for the abovementioned confounders. The association tended to be closer in men and young participants, compared with their counterparts.

CONCLUSIONS

High BMI was associated with a high risk of developing DM in the Chinese aged population. Thus, it is optimal for the aged population to maintain their body weight within a reasonable range to prevent chronic diseases.

Associations of fat and carbohydrate intake with becoming overweight and obese: an 11-year longitudinal cohort study

The effects of macronutrient intake on obesity are controversial. This research aims to investigate the associations between macronutrient intake and new-onset overweight/obesity. The relationship between the consumption of carbohydrate and total fat and obesity was assessed by the multivariable Cox model in this 11-year cohort, which included 6612 adults (3291 men and 3321 women) who were free of overweight and obesity at baseline. The dietary intake was recorded using a 24-h recall method for three consecutive days. Moreover, substitution models were developed to distinguish the effects of macronutrient composition alteration from energy intake modification. During 7·5 person years (interquartile range 4·3, 10·8) of follow-up, 1807 participants became overweight or obese. After adjusting for risk factors, the hazard ratio (HR) of overweight/obesity in extreme quintiles of fat was 1·48 (quintile 5 v. quintile 1, 95 % CI 1·16, 1·89; Ptrend = 0·02) in women. Additionally, replacing 5 % of energy from carbohydrate with equivalent energy from fat was associated with an estimated 4·3 % (HR 1·043, 95 % CI 1·007, 1·081) increase in overweight/obesity in women. Moreover, dietary carbohydrate was inversely associated with overweight/obesity (quintile 5 v. quintile 1, HR 0·70, 95 % CI 0·55, 0·89; Ptrend = 0·02) in women. Total fat was related to a higher risk of overweight/obesity, whereas high carbohydrate intake was related to a lower risk of overweight/obesity in women, which was not observed in men.

Adiposity and risk of death: A prospective cohort study of 463,002 adults

BACKGROUND

It is crucial to have simple and appropriate measures to identify people with adiposity-related risk. We compared the associations of mortality with body mass index (BMI), waist circumference (WC), waist-to-height ratio (WHtR), and body fat percentage (BF%) in a prospective cohort.

METHODS

A total of 463,002 adults were recruited between 1996 and 2017. Vital data were obtained from the National Death Registry System in Taiwan. Cox proportional hazards model was used to assess the associations of BMI, WC, WHtR, and BF% with mortality.

RESULT

Clear U-shape relationships were observed for all four parameters. In both men and women, the lowest risk of mortality was observed in the BMI category of 23.5-24.9 kg/m². Regarding WC, men in the third quintile (79.0-82.9 cm) and women in the fourth quintile (70.0-74.9 cm) had the lowest risk of mortality. For WHtR, men in the third quintile (0.46-0.49) and women in the fourth quintile (0.45-0.48) had the lowest risk of mortality. For BF%, both men and women in the fourth quintile (24.0-27.2% and 28.7-32.8%, respectively) had the lowest risk of mortality. The WC, WHtR, and BF% exhibited slightly associations with the risk of mortality across the three BMI categories [low (10.8-20.9 kg/m²), normal (21.0-27.4 kg/m²) and high (27.5-51.7 kg/m²)]. C-statistics of the four parameters ranged from 0.51 to 0.69.

CONCLUSION

Our results suggest that BMI should remain the primary marker for screening excessive adiposity. However, our findings also support the use of the WC, WHtR, and/or BF%, in addition to BMI when assessing the risk of mortality.

Impact of Individual and Combined Lifestyle Factors on Mortality in China: A Cohort Study

INTRODUCTION

Although numerous studies have suggested that lifestyle-related factors are associated with chronic diseases and preventable deaths, limited evidence is available for the Chinese population.

METHODS

This study established a prospective cohort of >360,000 residents on the basis of the Yinzhou Health Information System in China during 2004-2017 and calculated the combined effects of lifestyle-related factors, including BMI, smoking, alcohol consumption, and physical activity, using a points system. A Cox regression model estimated the combined effects of lifestyle-related factors on total mortality, and a competing risk model estimated the combined effects on cancer and cardiovascular disease mortality. All data analyses were conducted in 2018‒2019.

RESULTS

During 3,755,879 person-years of follow-up, 11,791 deaths were identified, including 4,983 from cancer and 3,143 from cardiovascular disease. Having a standard BMI, never smoking, never drinking, and engaging in physical activity more than 4 times per week had protective effects on total mortality. Overall, the risk of total and cause-specific mortality increased with the increment of risk score. Compared with subjects in the lowest quartile, the risk of total and cause-specific mortality peaked among individuals in the fourth quartile (total mortality: hazard ratio=1.87, 95% CI=1.77, 1.98; cancer mortality: hazard ratio=2.05, 95% CI=1.87, 2.25; cardiovascular disease mortality: hazard ratio=1.51, 95% CI=1.35, 1.68). Sensitivity analyses excluding individuals with follow-up <3 years did not materially change the results.

CONCLUSIONS

The combined effects of lifestyle-related factors, including BMI, smoking, alcohol drinking, and physical activity, are associated with total, cancer, and cardiovascular disease mortality among the Chinese population.

Mortality and recurrent vascular events after first incident stroke: a 9-year community-based study of 0·5 million Chinese adults

BACKGROUND

Stroke is a leading cause of death and disability worldwide. Despite considerable improvements in diagnosis and treatment, little is known about the short-term and long-term prognosis after a first stroke in low-income and middle-income countries, including China. We aimed to assess the short-term and long-term risk of recurrent stroke and mortality after a first stroke for each of the major pathological stroke types.

METHODS

This population-based cohort study included adults aged 35-74 years without disability who were recruited to the China Kadoorie Biobank (CKB). A baseline survey was conducted in ten geographical areas (five urban, five rural) in China, and participants had clinical measurements recorded. Participants were followed up by monitoring death registries and by electronic linkage to health registries and health insurance claims databases, with follow-up until Jan 1, 2017. Participants were excluded from analyses if they had a previous history of stroke, transient ischaemic attack, or ischaemic heart disease at baseline. All incidences of fatal and non-fatal stroke during the study period were recorded by type (ischaemic stroke, intracerebral haemorrhage, subarachnoid haemorrhage, and unspecified type). Primary outcome measures were 28-day mortality, recurrent stroke, major vascular events (recurrent stroke, myocardial infarction, or vascular death), vascular mortality, and all-cause mortality.

FINDINGS

Of 512 715 individuals in the CKB, 489 586 participants without previous ischaemic heart disease and stroke at recruitment were included, of whom 45 732 (42 073 [92%] confirmed by brain imaging) had a stroke during the study period. The mean age was 59·3 years (SD 9·8) for participants who had a stroke (54% women) and 50·8 years (10·3) for participants with no stroke (60% women). 36 588 (80%) of the incident cases of stroke were ischaemic stroke, 7440 (16%) were intracerebral haemorrhage, 702 (2%) were subarachnoid haemorrhage, and 1002 (2%) were an unspecified stroke type. 28-day mortality was 3% (95% CI 3-4) for ischaemic stroke, 47% (46-48)for intracerebral haemorrhage, 19% (17-22; 52% for rural areas and 32% for urban areas) subarachnoid haemorrhage, and 24% (22-27) for unspecified stroke. Among participants who survived stroke at 28 days, 41% (41-42) had recurrent stroke at 5 years (ischaemic stroke 41% [41-42], intracerebral haemorrhage 44% [42-46], subarachnoid haemorrhage 22% [18-27], unspecified stroke type 40% [35-44]) and mortality at 5 years was 17% ([17-18] ischaemic stroke 16% [15-16], intracerebral haemorrhage 28% [26-29], subarachnoid haemorrhage 16% [12-20], unspecified stroke type 15% [12-19]). After a first ischaemic stroke, 91% of recurrent strokes were also ischaemic stroke; after an intracerebral haemorrhage, 56% of recurrent strokes were intracerebral haemorrhage, and 41% of recurrent strokes were ischaemic stroke.

INTERPRETATION

After a first stroke, the risk of recurrence or death within 5 years was high among this population of Chinese adults. Urgent improvements to secondary prevention of stroke in China are needed to reduce these risks.

FUNDING

Wellcome Trust, Medical Research Council, British Heart Foundation, Cancer Research UK, Kadoorie Charitable Foundation, Chinese Ministry of Science and Technology, National Natural Science Foundation of China.

COPYRIGHT

© 2020 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 license.

Adiposity and mortality in older Chinese: an 11-year follow-up of the Guangzhou Biobank Cohort Study

Previous studies on Chinese showed mixed results describing the relationship between obesity and mortality. The optimum levels of body mass index (BMI) and waist circumference (WC) are inconsistent. In the Guangzhou Biobank Cohort Study, after excluding ever smokers and those with poor health, 19,405 Chinese (50+ years) recruited from 2003 to 2008 were followed-up until 2017. During an average follow-up of 11.5 (standard deviation = 2.3) years, 1,757 deaths were recorded. All-cause mortality showed a J-shaped association with BMI, with the lowest mortality risks at 22.5 kg/m² for both men and women. In those with BMI ≥ 22.5 kg/m², an increase of 5 kg/m² was associated with 29% higher all-cause mortality (hazard ratio (HR) = 1.29, 95% confidence interval (CI) 1.15–1.46), 30% higher cancer mortality (1.30, 95% CI 1.08–1.57), and 37% higher cardiovascular disease (CVD) mortality (1.37, 95% CI 1.13–1.67) after adjustment for potential confounders. In this first cohort study in one of the most economically developed cities in China, the lowest all-cause mortality was observed for a BMI of 22.5 kg/m² in all participants, and a WC of 78 cm in men and 72 cm in women.

The Dose-Response Associations of Sedentary Time with Chronic Diseases and the Risk for All-Cause Mortality Affected by Different Health Status: A Systematic Review and Meta-Analysis

PURPOSE

To determine the dose-response associations of sedentary behaviour with cardiovascular diseases (CVD), cancer, and all-cause mortality, and to examine whether the sedentary-associated all-cause mortality risk was affected by appearance of diabetes and hypertension, physical activity, and body mass index (BMI).

DESIGN

We carried out a systematic review and meta-analysis to search Medline, SportDiscus, and Web of Science for eligible studies.

SETTINGS

Prospective cohort studies that reported sedentary time and CVD, cancer, and mortality incidents.

MEASUREMENTS

Two authors independently extracted data based on predefined criteria. The effect estimates were evaluated by hazard ratios (HRs) with 95% confidences (CIs).

RESULTS

Twenty-four studies met the inclusion criteria. Sitting time showed dose-response associations with CVD, cancer, and all-cause mortality, with each 1-hour increment of sitting time daily accounting for HRs 1.04 (95% CIs 1.02-1.07), 1.01 (1.00-1.02), and 1.03 (1.02-1.03), respectively. The link between sitting time and CVD and all-cause mortality was non-linear (pnon-linear < 0.0001). The relationship between TV viewing and CVD and all-cause mortality was dose-dependent, with HRs 1.07 (1.06-1.09) and 1.04 (1.01-1.06) for per 1-hour increment of TV time every day, respectively. The regression was curved (pnon-linear < 0.0001). When the analysis was stratified by the percentage of diabetes and hypertension, BMI values, and physical activity levels, we found that higher BMI and a greater percentage of diabetes and hypertension further increased all-cause mortality risk in the most sedentary populations, whereas higher physical activity levels decreased it.

CONCLUSION

Sitting time and TV viewing significantly increased cardiovascular, cancer, and mortality risk; the associations were dose-dependent. More importantly, sedentary behaviour in combination with chronic diseases or high BMI increased all-cause mortality risk whereas physical activity was likely to alleviate the adverse associations.

Six-Year Incidence of Cardiometabolic Risk Factors in a Population-Based Cohort of Chinese Adults Followed From 2009 to 2015

Background China faces a substantial burden from cardiometabolic diseases, but longitudinal studies on a wide range of cardiometabolic risk factors are limited. We examined the 6-year incidence of 8 cardiometabolic risk factors in a diverse, population-based cohort. Methods and Results In the China Health and Nutrition Survey, anthropometry, blood pressure, and fasting blood samples were collected from 9621 adults (47.6% men) aged 18 to 99 years in 2009 who were followed into 2015. Using inverse probability weights to account for loss to follow-up, we estimated the 6-year incidence of 8 cardiometabolic risk factors and compared the incidence of each risk factor across age groups using inverse probability-weighted sex-stratified logistic regression models. Incidence was noted for the following cardiometabolic risk factors during 2009-2015: hypertension (systolic/diastolic blood pressure ≥140/90 mm Hg; men: 29.2%; women: 24.9%), high waist circumference/height ratio (≥0.5; men: 42.4%; women: 43.8%), and high total to HDL (high-density lipoprotein) cholesterol ratio (≥5; men: 17.0%; women: 14.5%). Older men and women (aged ≥65 years) had the highest incidence of hypertension. Incidence of high waist circumference/height ratio and high LDL (low-density lipoprotein) cholesterol (≥130 mg/ dL ) was highest among older (aged ≥65 years) women, whereas incidence of overweight (body mass index ≥25) and high triglycerides (≥150 mg/ dL ) was highest among younger (aged 18-35 and 35-50 years) men. Conclusions We found increases in cardiometabolic risk among Chinese adults during this recent, short, 6-year period that are higher than previous studies in China. The higher incidence of overweight and elevated dyslipidemia markers in younger versus older men portends an increasing burden of cardiometabolic diseases in China as the younger population ages.

Flawed methods and inappropriate conclusions for health policy on overweight and obesity: the Global BMI Mortality Collaboration meta-analysis

Guideline recommendations and health policy decisions rely on evidence from clinical and epidemiological studies. Adequate methodology and appropriate conclusions are essential to support healthcare and health policy decisions. An analysis of body mass index and mortality by the Global BMI Mortality Collaboration (GBMC) concluded that the association of excess body weight with higher mortality was similar worldwide and that overweight and obesity should be combated everywhere. To reach this conclusion, the GBMC used highly selected data, rather than a systematic approach. The GBMC initially chose individual participant data from 239 prospective studies with approximately 10.6 million participants. The GBMC then excluded over 60% of data and over 75% of fatal events by eliminating all cases with any reported disease at baseline or smoking history and all events within the first 5 years of follow-up. After applying these restrictions, the association of overweight with lower mortality was reversed and the association of obesity with higher mortality was increased. Given the major flaws in the selection process, in the adequacy of the data, in the data analysis, and in the interpretation, the GBMC conclusions should be viewed sceptically as a guide to action, either for clinical decisions or for public health in general. The flawed conclusion that overweight is uniformly associated with substantially increased risk of death and thus should be combated in any circumstances may lead not only to unjustified treatment efforts and potential harm in a wide range of clinical conditions but also to a tremendous waste of resources.

The association of under-weight and obesity with mortality after hip arthroplasty

Background

although many studies have demonstrated the association between body mass index (BMI) and many diseases, there is little evidence of postoperative mortality after hip arthroplasty. The aim of this study was to evaluate the association between BMI and mortality after hip arthroplasty in the older population.

Methods

a total of 3,627 older patients who underwent hip arthroplasty from 2010 to 2013 were included. We used Cox regression analysis to evaluate the association between BMI and mortality after hip arthroplasty. The hazard ratios (HRs) was calculated from 30 days, 31-365 days, and from the first day of surgery to the day of death during the study.

Results

under-weight (BMI under 18.5 kg/m2) is significantly associated with increased mortality (HR:1.423; 95% Confidence Interval (CI): 1.023-1.981) after hip arthroplasty compared to the normal range. However, in the short-term mortality within 30 days after surgery, both under-weight (HR: 2.368; 95%CI: 1.130-4.960) and obesity (25-29.9 kg/m2, HR: 2.023; 95%CI: 1.008-4.059) are associated with increased mortality.

Conclusion

our study suggested that under-weight is associated with increased risk of mortality after hip arthroplasty. Further, in a short-term outcome, obesity appear to be associated with increased mortality after hip arthroplasty within 30 days.

Predicted lean body mass, fat mass, and all cause and cause specific mortality in men: prospective US cohort study

OBJECTIVE

To investigate the association of predicted lean body mass, fat mass, and body mass index (BMI) with all cause and cause specific mortality in men.

DESIGN

Prospective cohort study.

SETTING

Health professionals in the United States PARTICIPANTS: 38 006 men (aged 40-75 years) from the Health Professionals Follow-up Study, followed up for death (1987-2012).

MAIN OUTCOME MEASURES

All cause and cause specific mortality.

RESULTS

Using validated anthropometric prediction equations previously developed from the National Health and Nutrition Examination Survey, lean body mass and fat mass were estimated for all participants. During a mean of 21.4 years of follow-up, 12 356 deaths were identified. A J shaped association was consistently observed between BMI and all cause mortality. Multivariable adjusted Cox models including predicted fat mass and lean body mass showed a strong positive monotonic association between predicted fat mass and all cause mortality. Compared with those in the lowest fifth of predicted fat mass, men in the highest fifth had a hazard ratio of 1.35 (95% confidence interval 1.26 to 1.46) for mortality from all causes. In contrast, a U shaped association was found between predicted lean body mass and all cause mortality. Compared with those in the lowest fifth of predicted lean body mass, men in the second to fourth fifths had 8-10% lower risk of mortality from all causes. In the restricted cubic spline models, the risk of all cause mortality was relatively flat until 21 kg of predicted fat mass and increased rapidly afterwards, with a hazard ratio of 1.22 (1.18 to 1.26) per standard deviation. For predicted lean body mass, a large reduction of the risk was seen within the lower range until 56 kg, with a hazard ratio of 0.87 (0.82 to 0.92) per standard deviation, which increased thereafter (P for non-linearity <0.001). For cause specific mortality, men in the highest fifth of predicted fat mass had hazard ratios of 1.67 (1.47 to 1.89) for cardiovascular disease, 1.24 (1.09 to 1.43) for cancer, and 1.26 (0.97 to 1.64) for respiratory disease. On the other hand, a U shaped association was found between predicted lean body mass and mortality from cardiovascular disease and cancer. However, a strong inverse association existed between predicted lean body mass and mortality from respiratory disease (P for trend <0.001).

CONCLUSIONS

The shape of the association between BMI and mortality was determined by the relation between two body components (lean body mass and fat mass) and mortality. This finding suggests that the "obesity paradox" controversy may be largely explained by low lean body mass, rather than low fat mass, in the lower range of BMI.

New anthropometric indices or old ones: which perform better in estimating cardiovascular risks in Chinese adults

Background

Various anthropometric indices can be used to estimate obesity, and it is important to determine which one is the best in predicting the risk of coronary heart disease (CHD) and to define the optimal cut-off point for the best index.

Methods

This cross-sectional study investigated a consecutive sample of 11,247 adults, who had lived in rural areas of China and were older than 35 years of age. Eight obesity indices, including the body mass index (BMI), waist circumference (WC), waist-to-hip ratio (WHR), waist-to-height ratio (WHtR), abdominal volume index (AVI), body adiposity index (BAI), body roundness index (BRI) and a body shape index (ABSI) were investigated. The risk of CHD was evaluated by the 10-year coronary event risk (Framingham risk score). Receiver operating characteristic (ROC) curve analyses were used to evaluate the predictive ability of the obesity indices for CHD risk.

Results

Of the whole population, 3636 (32.32%) participants had a risk score higher than 10%. Those who suffered medium or high CHD risk were more likely to have higher mean anthropometric indices, except for BMI in males. In the multivariate-adjusted logistic regression, all these anthropometric measurements were statistically associated with CHD risk in males. After adjusting for all the possible confounders, these anthropometric measurements, except for ABSI, remained as independent indicators of CHD risk in females. According to the ROC analyses, ABSI provided the largest area under the curve (AUC) value in males, and BMI showed the lowest AUC value, with AUC varying from 0.52 to 0.60. WHtR and BRI provided the largest AUC value in female, and similarly, BMI showed the lowest AUC value, with AUC varying from 0.59 to 0.70. The optimal cut-off values were as follows: WHtR (females: 0.54), BRI (females: 4.21), and ABSI (males: 0.078).

Conclusions

ABSI was the best anthropometric index for estimating CHD risk in males, and WHtR and BRI were the best indicators in females. Males should maintain an ABSI of less than 0.078, and females should maintain a WHtR of less than 0.54 or a BRI of less than 4.21.

Electronic supplementary material

The online version of this article (10.1186/s12872-018-0754-z) contains supplementary material, which is available to authorized users.

Early Life Growth Predictors of Childhood Adiposity Trajectories and Future Risk for Obesity: Birth to Twenty Cohort

BACKGROUND

There is growing evidence of variations in adiposity trajectories among individuals, but the influence of early life growth patterns on these trajectories is underresearched in low- and middle-income countries. Therefore, our aim was to examine the association between early life conditional weight gain and childhood adiposity trajectories.

METHODS

We previously identified distinct adiposity trajectories (four for girls and three for boys) in black South African children (boys = 877; girls = 947). The association between the trajectories and early life growth patterns, and future obesity risk was assessed by multivariate linear and multinomial logistic and logistic regressions. Conditional weight gain independent of height was computed for infancy (0-2 years) and early childhood (2-4 years).

RESULTS

Conditional weight gain before 5 years of age was significantly associated with early onset of obesity or overweight (excess weight) BMI trajectories in both boys and girls. In girls, greater conditional weight gain in infancy was associated with increased relative risk of being in the early-onset obese to morbid obese trajectory, with relative risk ratios of 2.03 (95% confidence interval: 1.17-3.52) compared to belonging to a BMI trajectory in the normal range. Boys and girls in the early-onset obesity or overweight BMI trajectories were more likely to be overweight or obese in early adulthood.

CONCLUSIONS

Excessive weight gain in infancy and early childhood, independent of linear growth, predicts childhood and adolescent BMI trajectories toward obesity. These results underscore the importance of early life factors in the development of obesity and other NCDs in later life.

Indispensable role of lipoprotein bound-ApoE in adipogenesis and endocytosis induced by postprandial TRL

Diet-associated obesity is coexisted with postprandial hypertriglyceridemia that indicates increased number of triglyceride-rich lipoproteins (TRL). This study aimed to investigate the effect of postprandial TRL-bound apolipoprotein E (ApoE) on adipogenesis and potential mechanisms. 3T3-L1 cells were cultured with (i) human TRL (h-TRL) with or without insulin, or (ii) TRL from wild type mice (WT-TRL) or ApoE knock-out mice (EKO-TRL) and insulin. The differentiating adipocytes were incubated with different kinds of TRL labeled by red fluorescence and confocal microscopy was performed. Receptor associated protein (RAP), heparin or both were added to inhibit low density lipoprotein receptor family receptors, heparan sulfate proteoglycan or both, respectively. With the aid of insulin, postprandial h-TRL or WT-TRL, instead of EKO-TRL, successfully induced adipogenesis. Confocal microscopy revealed red fluorescence in the differentiating adipocytes treated with h-TRL or WT-TRL, but not with EKO-TRL. RAP markedly reduced red fluorescence within the differentiating adipocytes, while heparin had little impact. The low density lipoprotein receptor related protein 1 protein showed upward trend with the increase of TRL concentrations. Taken together, lipoprotein-bound ApoE was required in both postprandial TRL-induced adipogenesis and TRL endocytosis by the differentiating adipocytes, the latter could be partially through low density lipoprotein receptor family dependent-pathway.

A meta-analysis but not a systematic review: an evaluation of the Global BMI Mortality Collaboration

Meta-analyses of individual participant data (MIPDs) offer many advantages and are considered the highest level of evidence. However, MIPDs can be seriously compromised when they are not solidly founded upon a systematic review. These data-intensive collaborative projects may be led by experts who already have deep knowledge of the literature in the field and of the results of published studies and how these results vary based on different analytical approaches. If investigators tailor the searches, eligibility criteria, and analysis plan of the MIPD, they run the risk of reaching foregone conclusions. We exemplify this potential bias in a MIPD on the association of body mass index with mortality conducted by a collaboration of outstanding and extremely knowledgeable investigators. Contrary to a previous meta-analysis of group data that used a systematic review approach, the MIPD did not seem to use a formal search: it considered 239 studies, of which the senior author was previously aware of at least 238, and it violated its own listed eligibility criteria to include those studies and exclude other studies. It also preferred an analysis plan that was also known to give a specific direction of effects in already published results of most of the included evidence. MIPDs where results of constituent studies are already largely known need safeguards to their validity. These may include careful systematic searches, adherence to the Preferred Reporting Items for Systematic Review and Meta-Analyses of individual participant data guidelines, and exploration of the robustness of results with different analyses. They should also avoid selective emphasis on foregone conclusions based on previously known results with specific analytical choices.

Comparative effects of the restriction method in two large observational studies of body mass index and mortality among adults

BACKGROUND

A method applied in some large studies of weight and mortality is to begin with a well-defined analytic cohort and use successive restrictions to control for methodologic bias and arrive at final analytic results.

MATERIALS AND METHODS

Two observational studies of body mass index and mortality allow a comparative assessment of these restrictions in very large data sets. One was a meta-analysis of individual participant data with a sample size of 8 million. The second was a study of a South Korean cohort with a sample size of 12 million. Both presented results for participants without pre-existing disease before and after restricting the sample to never-smokers and deleting the first 5 years of follow-up.

RESULTS

Initial results from both studies were generally similar, with hazard ratios (HRs) below 1 for overweight and above 1 for underweight and obesity. The meta-analysis showed higher HRs for overweight and obesity after the restrictions, including a change in the direction of the HR for overweight from 0·99 (95% CI: 0·98-1·01) to 1·11 (95% CI: 1·10, 1·11). The South Korean data showed little effect of the restrictions and the HR for overweight changed from 0·85 (95% CI: 0·84-0·86) to 0·91 (95% CI: 0·90, 0·91). The summary effect size for overweight was 0·90 (95% CI: 0·89-0·91) before restrictions and 1·02 (95% CI: 1·02, 1·03) after restrictions.

CONCLUSIONS

The effect of the restrictions is not consistent across studies, weakening the argument that analyses without such restrictions lack validity.

Body mass index and mortality in lung cancer patients: a systematic review and meta-analysis

Studies examining the relation of body mass index (BMI) and mortality in patients with lung cancer have shown diverse results. We conducted a meta-analysis to investigate the association using all available studies from January 1982 to October 2016. PubMed and EMBASE were searched to identify relevant studies. We calculated the summary hazard ratio (HR) and 95% confidence interval (CI) using random effects model. The dose-response relationship was assessed by random effects meta-regression model. Fifty-five articles from 51 studies involving 3 152 552 subjects (males, 54.8%) were included. The pooled results suggested that on average a high BMI decreased risk of death from lung cancer or all-cause. Each 5 kg/m² increase in BMI had a 12% lower risk of lung cancer-specific mortality (HR=0.88, 95% CI: 0.75-1.02, P=0.09) and a 14% lower risk of all-cause mortality (HR=0.86, 95% CI: 0.77-0.96, P<0.01). When stratifying by ethnicity, each 5 kg/m² increase in BMI was associated with 22% and 28% reduction, respectively, in the risk of lung cancer-specific mortality (P<0.01) and all-cause mortality (P<0.01) in Asians, but no association was found in Westerners (P=0.51 and P=0.53, respectively). In conclusion, lung cancer patients with a higher BMI have a longer survival than those with a lower BMI. Considering the significant heterogeneity between included studies, future studies are needed to confirm these findings.

Obesity Increases Risk-Adjusted Morbidity, Mortality, and Cost Following Cardiac Surgery

BACKGROUND

Despite the epidemic rise in obesity, few studies have evaluated the effect of obesity on cost following cardiac surgery. We hypothesized that increasing body mass index (BMI) is associated with worse risk-adjusted outcomes and higher cost.

METHODS AND RESULTS

Medical records for 13 637 consecutive patients who underwent coronary artery bypass grafting (9702), aortic (1535) or mitral (837) valve surgery, and combined valve-coronary artery bypass grafting (1663) procedures were extracted from a regional Society of Thoracic Surgeons certified database. Patients were stratified by BMI: normal to overweight (BMI 18.5-30), obese (BMI 30-40), and morbidly obese (BMI >40). Differences in outcomes and cost were compared between BMI strata and also modeled as a continuous function of BMI with adjustment for preoperative risk using Society of Thoracic Surgeons predictive risk indices. Morbidly obese patients incurred nearly 60% greater observed mortality than normal weight patients. Moreover, morbidly obese patients had greater than 2-fold increase in renal failure and 6.5-fold increase in deep sternal wound infection. After risk adjustment, a significant association was found between BMI and mortality (P<0.001) and major morbidity (P<0.001). The risk-adjusted odds ratio for mortality for morbidly obese patients was 1.57 (P=0.02) compared to normal patients. Importantly, risk-adjusted total hospital cost increased with BMI, with 17.2% higher costs in morbidly obese patients.

CONCLUSIONS

Higher BMI is associated with increased mortality, major morbidity, and cost for hospital care. As such, BMI should be more strongly considered in risk assessment and resource allocation.

Maternal and Early Childhood Determinants of Women's Body Size in Midlife: Overall Cohort and Sibling Analyses

Observational evidence suggests that adult body size has its roots earlier in life, yet few life-course studies have data on siblings with which to control for family-level confounding. Using prospective data from the Early Determinants of Mammographic Density Study (n = 1,108; 1959-2008), we examined the association of maternal prepregnancy body mass index (BMI; weight (kg)/height (m)2), gestational weight gain (GWG), birth size, and childhood growth factors with adult BMI in daughters at midlife using quantile, linear, and logistic regression models. We compared overall cohort findings (n = 1,108) with sibling differences (n = 246 sibling sets). Results derived by all 3 regression methods supported positive and independent associations of prepregnancy BMI, GWG, and percentile change in early childhood growth with BMI in daughters at midlife. Sibling analyses demonstrated that higher GWG was independently related to a higher adult BMI in daughters, particularly for the highest 90th quantile of adult BMI (β = 0.64 (standard error, 0.26) BMI units). Greater increases in weight percentiles between 1 and 4 years of age within siblings were also associated with higher adult BMI in the 75th quantile (β = 0.06 (standard error, 0.03) kg). Thus, even after consideration of the role of family-level fixed effects, maternal GWG and childhood weight gain are associated with adult body size in midlife.

Effect of limb preservation status and body mass index on the survival of patients with limb-threatening diabetic foot ulcers

AIMS

To evaluate the effect of limb preservation status and body mass index (BMI) on the survival of patients with diabetic foot ulcers (DFUs).

METHODS

A total of 1346 patients treated for limb-threatening DFUs at a major diabetic foot center in Taiwan from 2002 to 2009 were tracked until December 2012. The patients were classified into three groups: limb-preserved (n=858), minor lower-extremity amputation (LEA) (n=249), and major LEA (n=239). Clinical data during treatment were used for survival analysis.

RESULTS

With 729 deaths, the median survival time (MST) was 6.14 (95% CI 5.63-6.65) years. Major LEA and BMI were two independent factors associated with mortality after adjusting for age, diabetic duration, HbA1c level, comorbidities and peripheral artery diseases. The mortality hazard ratios for the minor and major LEA groups were 0.92 (95% CI 0.74-1.16) and 1.34 (95% CI 1.07-1.68), respectively, to the reference group (limb-preserved). After stratifying BMI into four categories (underweight, normal weight, overweight and obesity, according to the Taiwanese definition), the MSTs for each category were 2.57, 5.24, 7.47 and 7.85years, respectively (P for trend <0.01). This "obesity paradox" was not observed in the major LEA group (P for trend 0.25). For patients with LEA, the obesity patients had lower MST than those in overweight category (7.97 and 8.84 in minor and 3.25 and 5.42 in major LEA, respectively).

CONCLUSIONS

For the patients treated for DFUs, major - but not minor - LEA was associated with poor survival compared with the limb-preserved group. The MST had positive correlation with BMI levels for patients with limb-preserved and minor LEA, but not for those with major LEA.

Impact of alcohol consumption and body mass index on mortality from nonneoplastic liver diseases, upper aerodigestive tract cancers, and alcohol use disorders in Korean older middle-aged men: Prospective cohort study

Alcohol use is a leading risk factor for the global disease burden including liver diseases. However, the combined effect of alcohol use and body mass index (BMI) on alcohol-related diseases has seldom been examined. We examined whether alcohol consumption and BMI could act together to increase mortality from nonneoplastic liver diseases, upper aero-digestive tract (UADT) cancers, and alcohol use disorders (AUD) in middle-aged Korean men.107,735 men (mean age, 58.8 years) participated in a postal survey in 2004 and were followed until 2010, by linkage to national death records. Hazard ratios (HRs) of cause-specific death were calculated after adjustment for confounders.Each 5-drink (approximately 45 g alcohol) higher weekly alcohol consumption was associated with increased mortality, by approximately 70% for nonneoplastic liver disease mortality (HR = 1.70, P < 0.001), approximately 60% for UADT cancer mortality (HR = 1.64, P < 0.001), and approximately 70% for AUD mortality (HR = 1.71, P < 0.001). Generally, BMI was inversely associated with these alcohol-related diseases (HR per each 5 kg/m higher BMI = 0.18-0.46, P < 0.001 for each cause), while, in participants with BMI ≥25 kg/m, each 5 kg/m higher BMI was also associated with an elevated mortality from nonneoplastic liver diseases of approximately 150% (HR = 2.52, P = 0.001). Men with BMI < 21 kg/m and weekly alcohol consumption ≥14 drinks showed markedly higher mortality from nonneoplastic liver diseases (HR = 5.7), alcoholic liver diseases (HR = 9.3), UADT cancers (HR = 10.5), and esophageal cancer (HR = 15.5), compared to men drinking less than 1 drink/wk with BMI ≥25 kg/m. The combined effect of low BMI and high weekly alcohol consumption was 2.25- to 3.29-fold greater than the additive effect of each factor for these alcohol-related diseases (P < 0.05 for each cause).Alcohol consumption and low BMI were related to deaths from nonneoplastic liver diseases, UADT cancers, and AUD, with evidence of a supra-additive combined effect of both factors. High BMI was also related to deaths from nonneoplastic liver diseases. Men with a low BMI (<23 kg/m) are suggested to be prone to the harmful effects of alcohol.

Potential Impact of Time Trend of Life-Style Factors on Cardiovascular Disease Burden in China

BACKGROUND

Cardiovascular disease (CVD) is a leading cause of death in China. Evaluation of risk factors and their impacts on disease burden is important for future public health initiatives and policy making.

OBJECTIVES

The study used data from a cohort of the China Health and Nutrition Survey to estimate time trends in cardiovascular risk factors from 1991 to 2011.

METHODS

We applied the comparative risk assessment method to estimate the number of CVD events attributable to all nonoptimal levels (e.g., theoretical-minimum-risk exposure distribution [TMRED]) of each risk factor.

RESULTS

In 2011, high blood pressure, high low-density lipoprotein cholesterol, and high blood glucose were associated with 3.1, 1.4, and 0.9 million CVD events in China, respectively. Increase in body mass index was associated with an increase in attributable CVD events, from 0.5 to 1.1 million between 1991 and 2011, whereas decreased physical activity was associated with a 0.7-million increase in attributable CVD events. In 2011, 53.4% of men used tobacco, estimated to be responsible for 30.1% of CVD burden in men. Dietary quality improved, but remained suboptimal; mean intakes were 5.4 (TMRED: 2.0) g/day for sodium, 67.7 (TMRED: 300.0) g/day for fruits, 6.2 (TMRED: 114.0) g/day for nuts, and 25.0 (TMRED: 250.0) mg/day for marine omega-3 fatty acids in 2011.

CONCLUSIONS

High blood pressure remains the most important individual risk factor related to CVD burden in China. Increased body mass index and decreased physical activity were also associated with the increase in CVD burden from 1991 to 2011. High rates of tobacco use in men and unhealthy dietary factors continue to contribute to the burden of CVD in China.

Body Mass Index and Mortality: A 10-Year Prospective Study in China

Although several studies have evaluated the role of body weight as a risk factor for mortality, most studies have been conducted in Western populations and the findings remain controversial. We performed a prospective study to examine the association between body mass index (BMI) and all-cause mortality in Yinzhou District, Ningbo, China. At baseline, 384,533 subjects were recruited through the Yinzhou Health Information System between 2004 and 2009. The final analysis was restricted to 372,793 participants (178,333 men and 194,460 women) aged 18 years and older. Cox proportional hazards models were used to estimate hazard ratios(HRs) and 95% confidence intervals(CIs). We found an increased risk of all-cause mortality among individuals with BMI levels <22.5-24.9, although several groups were not statistically significant-adjusted HRs for persons with BMIs of <15.0, 15.0-17.4, 17.5-19.9, and 20.0-22.4 were 1.61(95% CI: 1.17-2.23), 1.07(0.94-1.20), 1.04(0.98-1.10), 1.06(1.02-1.11), respectively. In the upper BMI range, subjects with BMIs of 25.0-34.9 had a reduced risk of all-cause mortality. Sensitivity analyses excluding smokers, those with prevalent chronic disease or those with less than four years of follow-up did not materially alter these results. Our findings provide evidence for an inverse association of BMI and mortality in this population.

BMI and all cause mortality: systematic review and non-linear dose-response meta-analysis of 230 cohort studies with 3.74 million deaths among 30.3 million participants

OBJECTIVE

To conduct a systematic review and meta-analysis of cohort studies of body mass index (BMI) and the risk of all cause mortality, and to clarify the shape and the nadir of the dose-response curve, and the influence on the results of confounding from smoking, weight loss associated with disease, and preclinical disease.

DATA SOURCES

PubMed and Embase databases searched up to 23 September 2015.

STUDY SELECTION

Cohort studies that reported adjusted risk estimates for at least three categories of BMI in relation to all cause mortality.

DATA SYNTHESIS

Summary relative risks were calculated with random effects models. Non-linear associations were explored with fractional polynomial models.

RESULTS

230 cohort studies (207 publications) were included. The analysis of never smokers included 53 cohort studies (44 risk estimates) with >738 144 deaths and >9 976 077 participants. The analysis of all participants included 228 cohort studies (198 risk estimates) with >3 744 722 deaths among 30 233 329 participants. The summary relative risk for a 5 unit increment in BMI was 1.18 (95% confidence interval 1.15 to 1.21; I(2)=95%, n=44) among never smokers, 1.21 (1.18 to 1.25; I(2)=93%, n=25) among healthy never smokers, 1.27 (1.21 to 1.33; I(2)=89%, n=11) among healthy never smokers with exclusion of early follow-up, and 1.05 (1.04 to 1.07; I(2)=97%, n=198) among all participants. There was a J shaped dose-response relation in never smokers (Pnon-linearity <0.001), and the lowest risk was observed at BMI 23-24 in never smokers, 22-23 in healthy never smokers, and 20-22 in studies of never smokers with ≥20 years' follow-up. In contrast there was a U shaped association between BMI and mortality in analyses with a greater potential for bias including all participants, current, former, or ever smokers, and in studies with a short duration of follow-up (<5 years or <10 years), or with moderate study quality scores.

CONCLUSION

Overweight and obesity is associated with increased risk of all cause mortality and the nadir of the curve was observed at BMI 23-24 among never smokers, 22-23 among healthy never smokers, and 20-22 with longer durations of follow-up. The increased risk of mortality observed in underweight people could at least partly be caused by residual confounding from prediagnostic disease. Lack of exclusion of ever smokers, people with prevalent and preclinical disease, and early follow-up could bias the results towards a more U shaped association.

Body Mass Index and Cancer Mortality Among Korean Older Middle-Aged Men: A Prospective Cohort Study

The association of body mass index (BMI; kg/m) with overall and site-specific cancer mortality in Asians is not well understood. A total of 113,478 men from the Korean Veterans Health Study who returned a postal survey in 2004 were followed up until 2010. The adjusted hazard ratios (HRs) of cancer mortality were calculated using a Cox model. During 6.4 years of follow-up, 3478 men died from cancer. A reverse J-curve association with a nadir at 25.0 to 27.4 kg/m was observed. Below 25 kg/m, the HRs of death for each 5 kg/m decrease in BMI were 1.72 (95% confidence interval = 1.57-1.90) for overall cancer; 3.63 (2.57-5.12) for upper aerodigestive tract (UADT) cancers, including oral cavity and larynx [HR = 4.21 (2.18-8.12)] and esophagus [HR = 2.96 (1.82-4.81)] cancers; 1.52 (1.35-1.71) for non-UADT and non-lung cancers, including stomach [HR = 2.72 (2.13-3.48)] and large intestine [HR = 1.68 (1.20-2.36)] cancers; and 1.93 (1.59-2.34) for lung cancer. In the range of 25 to 47 kg/m, the HRs for each 5 kg/m increase in BMI were 1.27 (1.03-1.56) for overall cancer mortality and 1.57 (1.02-2.43) for lung cancer mortality. In individuals <25 kg/m, inverse associations with mortality from overall cancer and non-UADT and non-lung cancer were stronger in never-smokers than in current smokers. Both low and high BMI were strong predictors of mortality from overall and several site-specific cancers in Korean men. Further research is needed to evaluate whether interventions involving weight change (loss or gain) reduce the risk of cancer or improve the survival.

Underweight is a risk factor for atrial fibrillation: A nationwide population-based study

BACKGROUND

Obesity is a well-known risk factor for development of atrial fibrillation (AF). However, the impact of underweight on AF has not been previously recognized. We sought to determine the risk of AF in subjects with underweight in this study.

METHODS

We analyzed clinical data from a total of 132,063 individuals with the age of 40years or older who received health care checkups arranged by the national insurance program between 2003 and 2004. Newly diagnosed nonvalvular AF was identified using claim data during a median follow-up duration of 9.0years.

RESULTS

The mean body mass index (BMI) of patients was 23.9kg/m(2), and 3,323 individuals (2.5%) were classified as being underweight (BMI <18.5kg/m(2)). During the study period, 3,237 individuals (2.5%) developed AF. There was a U-shaped relationship between BMI and AF occurrence: Each 1.0kg/m(2) increase of BMI above 20kg/m(2) was associated with a 6% increased risk of AF (p<0.001), while each 1.0kg/m(2) lower BMI below 20kg/m(2) was associated with a 13% increased risk of AF (p<0.001) after multivariable adjustment. Underweight was significantly associated with 23% increased risk of AF, while obesity classes I and II were with 26% and 120% increased risk of AF, respectively. Excess risk of AF in the underweight was independent of thyroid disease, chronic lung disease, or history of malignancy, and was not attributable to cigarette smoking, low socioeconomic status, excessive physical activity, or heavy alcohol consumption.

CONCLUSION

BMI has a U-shaped relationship with the risk of AF. Underweight was an independent risk factor for AF independent of confounding factors such as chronic lung disease and malignancy. These findings suggest that underweight is associated with biological effects that contribute to the development of AF.

The impact of genetic variants on BMI increase during childhood versus adulthood

BACKGROUND

Genetic variants that predispose individuals to obesity may have differing influences during childhood versus adulthood, and additive effects of such variants are likely to occur. Our ongoing studies to identify genetic determinants of obesity in American Indians have identified 67 single-nucleotide polymorphisms (SNPs) that reproducibly associate with maximum lifetime non-diabetic body mass index (BMI). This study aimed to identify when, during the lifetime, these variants have their greatest impact on BMI increase.

SUBJECTS/METHODS

A total of 5906 Native Americans of predominantly Pima Indian heritage with repeated measures of BMI between the ages of 5 and 45 years were included in this study. The association between each SNP with the rates of BMI increase during childhood (5-19 years) and adulthood (20-45 years) were assessed separately. The significant SNPs were used to calculate a cumulative allelic risk score (ARS) for childhood and adulthood, respectively, to assess the additive effect of these variants within each period of life.

RESULTS

The majority of these SNPs (36 of 67) were associated with rate of BMI increase during childhood (P-value range: 0.00004-0.05), whereas only nine SNPs were associated with rate of BMI change during adulthood (P-value range: 0.002-0.02). These 36 SNPs associated with childhood BMI gain likely had a cumulative effect as a higher childhood-ARS associated with rate of BMI change (β=0.032 kg m(-2) per year per risk allele, 95% confidence interval: 0.027-0.036, P<0.0001), such that at age 19 years, individuals with the highest number of risk alleles had a BMI of 10.2 kg m(-2) greater than subjects with the lowest number of risk alleles.

CONCLUSIONS

Overall, our data indicates that genetic polymorphisms associated with lifetime BMI may influence the rate of BMI increase during different periods in the life course. The majority of these polymorphisms have a larger impact on BMI during childhood, providing further evidence that prevention of obesity will need to begin early in life.

Underweight but metabolically abnormal phenotype: Metabolic features and its association with cardiovascular disease

BACKGROUND

Previous studies revealed that among people with normal and high body mass index (BMI), metabolic abnormalities contribute to the increased risk of cardiovascular disease (CVD). However, studies investigating the metabolic features and its association with CVD are limited.

METHODS

A national representative sample of adult population in China was used. Underweight was defined as BMI <18.5kg/m(2). Participants who had less than 2 criteria of metabolic syndrome were classified as metabolically healthy; those who had 2 or more criteria of metabolic syndrome were classified as metabolically abnormal. Presence of CVD and albuminuria were compared among groups stratified by BMI and metabolic status.

RESULTS

Among 46308 participants, 2267 (4.6%) were classified as underweight; and 372 (16.4%) of them were identified as metabolically abnormal. Metabolic features were comparable between underweight but metabolically abnormal participants and obese participants. Compared with participants with normal weight and normal metabolic features, the underweight but metabolically abnormal participants were more likely to have CVD and albuminuria, with an adjusted odds ratio of 2.33 (95% confidence interval (CI) 1.34-4.05) and 2.56 (95% CI 1.86-3.52), respectively. Among underweight participants, factors associated with metabolic abnormal phenotype included leisure time physical inactivity, mild occupational physical activity, and waist circumference.

CONCLUSIONS

Metabolically abnormal phenotype is not rare among underweight population in China, and preventive strategy against CVD should also be considered in that population.

Abdominal obesity is strongly associated with Cardiovascular Disease and its Risk Factors in Elderly and very Elderly Community-dwelling Chinese

Obesity is usually considered to predispose to atherosclerotic cardiovascular disease (ASCVD) but milder degrees of obesity or overweight may be protective in some elderly populations. We examined the relationships between general and abdominal obesity indices with ASCVD and its risk factors in elderly (aged ≥65 years) Shanghai community residents Among the 3950 participants, 21.5% had ASCVD, 56.2% had body mass index (BMI) ≥24 kg/m2, 50.1% had high waist circumference (WC) and 77.1% had waist-to-height ratio (WHtR) ≥0.50. WHtR increased with age in both men and women whereas WC increased with age only in women and BMI decreased with age only in men. The optimal WHtR cut-off value to predict the risk of ASCVD determined by receiver operating characteristic analysis was WHtR ≥0.53 with a prevalence of 55.8%. Having abdominal obesity was significantly associated with prevalent ASCVD with WHtR ≥0.53 having a higher value for the odds ratio than high WC, whereas high BMI was not associated. All three indices predicted high glucose, triglycerides and hsCRP levels but only the WHtR ≥0.53 showed a significant association with physical activity. Abdominal obesity indices, but not BMI, predicted prevalent ASCVD and its risk factors in this elderly Chinese population.

Underweight and mortality

OBJECTIVE

According to most prospective studies, being underweight (BMI<18·5 kg/m2) is associated with significantly higher mortality than being of normal weight, especially among smokers. We aimed to explore in a generally lean population whether being underweight is significantly associated with increased all-cause mortality.

DESIGN

Prospective cohort study.

SETTING

Korea Medical Insurance Corporation study with 14 years of follow-up.

SUBJECTS

After excluding deaths within the first 5 years of follow-up (1993-1997) to minimize reverse causation and excluding participants without information about smoking and health status, 94 133 men and 48 496 women aged 35-59 years in 1990 were included.

RESULTS

We documented 5411 (5·7 %) deaths in men and 762 (1·6 %) in women. Among never smokers, hazard ratios (HR) for underweight individuals were not significantly higher than those for normal-weight individuals (BMI=18·5-22·9 kg/m2): HR=0·87 (95 % CI 0·41, 1·84, P=0·72) for underweight men and HR=1·12 (95 % CI 0·76, 1·65, P=0·58) for underweight women. Among ex-smokers, HR=0·86 (95 % CI 0·38, 1·93, P=0·72) for underweight men and HR=3·77 (95 % CI 0·42, 32·29, P=0·24) for underweight women. Among current smokers, HR=1·60 (95 % CI 1·28, 2·01, P<0·001) for underweight men and HR=2·07 (95 % CI 0·43, 9·94, P=0·36) for underweight women.

CONCLUSIONS

The present study does not support that being underweight per se is associated with increased all-cause mortality in Korean men and women.

Association of Body Mass Index and Body Mass Index Change with Mortality in Incident Peritoneal Dialysis Patients

Although high body mass index (BMI) appears to confer a survival advantage in hemodialysis patients, the association of BMI with mortality in continuous ambulatory peritoneal dialysis (CAPD) patients is uncertain. We enrolled incident CAPD patients and BMI was categorized according to World Health Organization classification for Asian population. BMI at baseline and one year after the initiation of peritoneal dialysis (PD) treatment was assessed to calculate the BMI change (∆BMI). Patients were split into four categories according quartiles of ∆BMI. Kaplan-Meier method and Cox regression proportional hazard analysis were performed to assess the association of BMI on outcomes. A total of 1263 CAPD patients were included, with a mean age of 47.8 ± 15.0 years, a mean BMI of 21.58 ± 3.13 kg/m². During a median follow-up of 25.3 months, obesity was associated with increased risk for cardiovascular diseases (CVD) death (adjusted hazard ratio (AHR) 2.01; 95% CI 1.14, 3.54), but not all-cause mortality. Additionally, patients with more BMI decline (>0.80%) during the first year after CAPD initiation had an elevated risk for both all-cause (AHR: 2.21, 95% CI 1.23-3.95) and CVD mortality (AHR 2.31, 95% CI 1.11, 4.84), which was independent of baseline BMI values.