Migration, blood pressure pattern, and hypertension: the Yi Migrant Study

The Prevalence of Non-infectious Diseases Among Overseas Chinese Workers in 2018

Background

With the "Belt and Road" initiative, more Chinese citizens have gone abroad to engage in overseas labor activities. Few studies have investigated the prevalence of non-infectious diseases among Chinese overseas workers. This study seeks to fill the gap and illustrate the relevant diseases in a population of Chinese overseas workers.

Methods

The health records of 13,529 Chinese migrant workers (12,917 males, mean age 41.3 ± 8.7 years, and 612 females, mean age 33.1 ± 10.2 years) who visited the International Travel Health Care Center in Anhui province were obtained. Chi-square test and binary logistic regression models were used to analyze the associations between the prevalence of non-infectious diseases and sex, as well as the association between non-infectious diseases and length of stay abroad.

Results

In this study, 34.6% of overseas workers were found to have one or more types of non-infectious diseases. Hypertension had the highest prevalence (9.58%). Hypertension, fatty liver, renal disease and abnormal liver function tests were more prevalent among male workers than among female workers, while anemia and abnormal urinalysis were more prevalent among female workers. The prevalence of hypertension, renal diseases, liver diseases and gallbladder diseases increased with the length of stay abroad.

Conclusion

Non-infectious diseases including cardiovascular diseases, diabetes, and chronic respiratory diseases were highly prevalent among Chinese overseas workers. Hence the monitoring of non-infectious diseases needs to be enhanced to reduce China's overall disease burden in the future.

MC4R Gene Polymorphisms Interact With the Urbanized Living Environment on Obesity: Results From the Yi Migrant Study

Objectives: This study aimed to determine the association of MC4R gene polymorphisms (rs17782313 and rs12970134) and urbanized living environment and the gene–environment interaction with obesity in Yi people in China.

Methods: A 1:2 frequency-matched case–control study based on the cross-sectional data was designed. Those with BMI ≥28 kg/m² were included as the case group. The age- and sex-matched controls were selected from those with BMI <24 kg/m². Unconditional logistic models were used to determine the association of SNPs with obesity. Additive interaction was evaluated by calculating relative excess risk due to interaction (RERI), attributable proportion due to interaction (AP), and synergy index (SI).

Results: A total of 322 cases and 643 controls were included. After adjustment, allele C of rs17782313 was significantly associated with obesity (additive model, OR = 1.52, 95%CI: 1.18–1.96) in Yi people. A similar association was found in allele A of rs12970134 (additive model, OR = 1.45, 95%CI: 1.13–1.89). Yi rural-to-urban migrants were found at 2.59-fold (95%CI: 1.70–3.95) higher odds of obesity than Yi farmers. Additive interactions were found between the two SNPs and rural-to-urban migration (rs17782313: AP = 0.65, 95%CI: 0.22–1.09; rs12970134: AP = 0.59, 95%CI: 0.02–1.17).

Conclusion:MC4R gene polymorphisms positively interacted with the urbanized living environment on obesity in Yi people. The effect of the MC4R gene on obesity was modified by the living environment.

Neighborhood Exposures and Blood Pressure Outcomes: A Cross-Sectional Environmental Study among 19-53 Years-Old Parsis in Mumbai

The correlation between high blood pressure (BP) and urban neighborhood-level environmental determinants is understudied in low-income and middle-income countries (LMICs). We hypothesized that neighborhoods constitute exposures that affect resident-behaviors, metabolism and increased susceptibility to high BP. We studied urban clusters of Mumbai-Parsis (Zoroastrians), a founder population group, to minimize genetic variation and maximize exposure assessment. Participants from four neighborhoods were 19–53 years old and comprised 756 females and 774 males. We recorded healthy BPs (≤120/80 mmHg) in 59%, pre-hypertensive (≥121–139/81–89 mmHg) in 21% and high BP (≥140/90 mmHg) in 21% of the participants. A family history of hypertension had no correlation with high BP. We used the Neighborhood Accessibility Framework to compile a questionnaire in order to collect data on participants’ perception of space, third places, streetscape and experience, land use, connectivity, surveillance, pedestrian safety and public transport. Our results suggested that participants in neighborhoods with poorer BP outcomes reported lower accessibility scores for space, streetscape and experience, third places and connectivity. Our study evaluates how neighborhood-level determinants affect BP outcomes in order to contribute to the body of knowledge on primary preventive measures for high BP in urban LMIC populations. We concluded that neighborhood exposures affect resident-behaviors, which cause metabolic changes and increase susceptibility to high BP.

Home Blood Pressure Monitoring Devices: Device Performance in an Alaska Native and American Indian Population

Objectives: Home blood pressure monitoring (HBPM) is an important component of blood pressure (BP) management. We assessed performance of two HBPM devices among Alaska Native and American Indian people (ANAIs). Methods: We measured BP using Omron BP786 arm cuff, Omron BP654 wrist cuff, and Baum aneroid sphygmomanometer in 100 ANAIs. Performance was assessed with intraclass correlation, paired t-tests, and calibration models. Results: Compared to sphygmomanometer, average BP was higher for wrist cuff (systolic = 4.8 mmHg and diastolic = 3.6 mmHg) and varied for arm cuff (systolic = -1.5 mmHg and diastolic = 2.5 mmHg). Calibration increased performance from grade B to A for arm cuff and from D to B for wrist cuff. Calibration increased false negatives and decreased false positives. Discussion: The arm HBPM device is more accurate than the wrist cuff among ANAIs with hypertension. Most patients are willing to use the arm cuff when accuracy is discussed.

Association of Normal Systolic Blood Pressure Level With Cardiovascular Disease in the Absence of Risk Factors

Importance

The risk of atherosclerotic cardiovascular disease (ASCVD) at currently defined normal systolic blood pressure (SBP) levels in persons without ASCVD risk factors based on current definitions is not well defined.

Objective

To examine the association of SBP levels with coronary artery calcium and ASCVD in persons without hypertension or other traditional ASCVD risk factors based on current definitions.

Design, Setting, and Participants

A cohort of 1457 participants free of ASCVD from the Multi-Ethnic Study of Atherosclerosis who were without dyslipidemia (low-density lipoprotein cholesterol level ≥160 mg/dL or high-density lipoprotein cholesterol level <40 mg/dL), diabetes (fasting glucose level ≥126 mg/dL), treatment for hyperlipidemia or diabetes, or current tobacco use, and had an SBP level between 90 and 129 mm Hg. Participants receiving hypertension medication were excluded. Coronary artery calcium was classified as absent or present and adjusted hazard ratios (aHRs) were calculated for incident ASCVD. The study was conducted from March 27, 2018, to February 12, 2020.

Exposures

Systolic blood pressure.

Main Outcomes and Measures

Presence or absence of coronary artery calcium and incident ASCVD events.

Results

Of the 1457 participants, 894 were women (61.4%); mean (SD) age was 58.1 (9.8) years and mean (SD) follow-up was 14.5 (3.9) years. There was an increase in traditional ASCVD risk factors, coronary artery calcium, and incident ASCVD events with increasing SBP levels. The aHR for ASCVD was 1.53 (95% CI, 1.17-1.99) for every 10-mm Hg increase in SBP levels. Compared with persons with SBP levels 90 to 99 mm Hg, the aHR for ASCVD risk was 3.00 (95% CI, 1.01-8.88) for SBP levels 100 to 109 mm Hg, 3.10 (95% CI, 1.03-9.28) for SBP levels 110 to 119 mm Hg, and 4.58 (95% CI, 1.47-14.27) for SBP levels 120 to 129 mm Hg.

Conclusions and Relevance

Beginning at an SBP level as low as 90 mm Hg, there appears to be a stepwise increase in the presence of coronary artery calcium and the risk of incident ASCVD with increasing SBP levels. These results highlight the importance of primordial prevention for SBP level increase and other traditional ASCVD risk factors, which generally seem to have similar trajectories of graded increase in risk within values traditionally considered to be normal.

Association of Socioeconomic Status and Overweight/Obesity in Rural-to-Urban Migrants: Different Effects by Age at Arrival

This study aims to investigate the association between socioeconomic status and overweight/obesity in rural-to-urban Yi migrants in China, and to explore whether the association varied by the age at arriving urban areas. The cross-sectional population-based data from the Yi Migrants Study in 2015 was used, which included 1,181 Yi migrants aged 20–80 years. Socioeconomic status was evaluated by education level, personal annual income, and a composited variable (socioeconomic status index, SESI). Measured weight and height were used to calculate BMI and to define overweight/obesity (BMI ≥ 24 kg/m²). The results suggested that the association of income and SESI with overweight/obesity was not significant when age at arrival (two groups, <20 and ≥20 years) was considered as a covariate. In the stratification analysis, reversed association was observed in the two groups of age at arrival. In migrants of <20 years of age at arrival, higher level of education and SESI were related to decreased risk of overweight/obesity. In contrary, in those of ≥20 years at arrival, higher socioeconomic status level was found to be related to increased risk. Our findings suggest that the effect of socioeconomic status on overweight/obesity was modified by the age at arrival in Yi migrants. Especially, the association between socioeconomic status and overweight/obesity was negative when migration before 20 years of age, and transfer to positive after 20 years.

Association between age at arrival, duration of migration, and overweight/obesity in Chinese rural-to-urban migrants: the Yi migrant study

Background:

Urbanization in China is rapidly proceeding, but rural-to-urban migration and its association with overweight and obesity is not well studied. This study aimed to explore the age at arrival, duration of migration, and the corresponding association with overweight/obesity in Yi migrants in China.

Methods:

A cross-sectional study was conducted in rural and urban areas in 2015 in Sichuan province, China. Demographic characteristics, lifestyle factors, and anthropometry were collected. General linear regression models were used to assess the effect of duration of migration (1–10, 11–20, 21–30, and >30 years) on body mass index (BMI). Multi-variable logistic regression was used to examine the association between duration of migration and overweight/obesity (BMI ≥ 25 kg/m²).

Results:

A total of 3056 Yi people (1894 Yi farmers and 1162 Yi migrants) aged 20 to 80 years were enrolled. After adjusting for age, sex, and other potential confounders, Yi migrants had 1.71 kg/m² (95% confidence interval [CI]: 1.36–2.06) higher BMI and a 2.13-fold (95% CI: 1.71–2.65) higher risk of overweight/obesity than Yi farmers. In Yi migrants, stratified by age at arrival, no significant association between duration of migration and overweight/obesity was observed in those who were 0 to 20 years old at arrival. In comparison, in migrants >20 years old at arrival, compared with the reference group (1–10 years), long-term migration (>30 years) was found to be associated with overweight/obesity after adjustment (odds ratio: 1.85, 95% CI: 1.04–3.29).

Conclusions:

Yi migrants were observed to have greater risk of overweight/obesity than Yi farmers. In Yi migrants, the risk of overweight/obesity increased according to the duration of migration, especially in those who were older upon their arrival.

Impact of Perception of Green Space for Health Promotion on Willingness to Use Parks and Actual Use among Young Urban Residents

Promoting the use of green space is a fundamental way to improve physical and mental health and to enhance the quality of life of urban residents. In response to increasing demand for green space in cities, the impact of perception of green space for health promotion on willingness to use parks and actual use among young urban residents was investigated in this study. A total of 1135 young residents (ages 18–35) in three cities in China were surveyed by online questionnaire. A group of multiple regression models was constructed to investigate the influencing perception factors of participants’ willingness to use parks and actual use. The results revealed that the young residents’ perception of green space components for health promotion (green space access, types, sizes, plants, water, sensory features, microclimate environments and amenity facilities) had a greater effect on their willingness to use parks and to promote health, while it was less influential with respect to their actual park use behavior (frequency and duration). Among these variables, green space access is a critical concern for willingness to use toward parks. The disparities of perception of green space for health promotion effect on willingness to use a park and actual use provide a better understanding of the psychological factors affecting park use among young residents. The findings also provided some implications for public health policymakers, urban planners and landscape architects in designing parks to encourage visitation by young people.

Regional and Geographical Disparities in Body Mass Index (BMI) Among Chinese Older Adults: The Chinese Longitudinal Healthy Longevity Survey

This study examined the regional and geographical disparities in body mass index (BMI) among Chinese older adults. Using panel data from the Chinese Longitudinal Healthy Longevity Survey, participants included 3,740 older adults (age ≥ 65 years) who answered all three waves of the survey (2009-2014). Sex-stratified and multistate Cox regression was used to examine the disparities in BMI change. Results showed that both older males and older females who resided in the central-south had lower rates of weight change from nonobese to obese, compared with those from the east. Older females from urban regions had higher rate of weight change from nonobese to obese, compared with rural participants (hazard ratio [HR]: 1.35, 95% confidence interval [CI] = [1.13, 1.60]; p < .01). However, there were no disparities between urban and rural areas among older males (p > .05). These results provided practical implications for regional and geographical disparities in BMI among Chinese older adults.

Secular Trends of the Impact of Overweight and Obesity on Hypertension in Yi People: Yi Migrant Study, 1996-2015

Background

Rising hypertension prevalence, coupled with increasing overweight and obesity rates, has been observed in Yi people. Moreover, the growing blood pressure level among Yi people was mostly attributable to the continuous increase of body mass index (BMI). However, little is known about the trend of association between them.

Methods

Consequently, we investigated the impact of overweight/obesity on hypertension over three periods (1996, 2007-2008, 2015) using data from Yi Migrant Study (n = 8749). The Yi Migrant Study incorporated three successive cross-sectional studies which were implemented by the same team with consistent protocols.

Results

Compared with period 1 (1996), the influence of overweight/obesity on hypertension risk significantly increased in period 2 (2007-2008) and period 3 (2015); relative excess risk due to interaction (RERI) was 1.59 (95% CI: 0.12, 3.05) and 1.41 (95% CI: 0.30, 2.78), respectively. Meanwhile, the overweight/obese population in period 3 did not show hypertension risk higher than that in period 2 (RERI = 0.15; 95% CI: -0.76, 1.07). Additionally, we observed a continuously growing trend of hypertension risk among normal weight Yi people.

Conclusions

During the past two decades, there was a significant increase in the association between overweight/obesity and hypertension in Yi people, whereas the increasing trend has leveled off in more recent years. These findings suggest that overweight/obesity and hypertension are becoming more epidemic comorbidity over time. Interventions to prevent hypertension should focus not only on the overweight/obese population, but also on those with normal weight.

Is agricultural engagement associated with lower incidence or prevalence of cardiovascular diseases and cardiovascular disease risk factors? A systematic review of observational studies from low- and middle-income countries

Non-communicable diseases, such as cardiovascular diseases (CVDs), diabetes and cancer account for more than half of the global disease burden, and 75% of related deaths occur in low- and middle-income countries (LMICs). Despite large regional variations in CVD incidence and prevalence, CVDs remain the leading causes of death worldwide. With urbanisation, developing nations are undergoing unprecedented labour-force transitions out of agriculture and into types of non-agricultural employment, mainly in the industry and service sectors. There are few studies on the effect of these transitions on CVDs and CVD risk factors in LMICs. We systematically searched MEDLINE, PubMed, EMBASE and the Cochrane Library from January 1950 to January 2017 to assess the association of engaging in agriculture compared to types of non-agricultural employment (e.g. services and manufacturing) with CVD incidence, prevalence and risk factors. Studies were included if they: included participants who engaged in agriculture and participants who did not engage in agriculture; measured atherosclerotic CVDs or their modifiable risk factors; and involved adults from LMICs. We assessed the quality of evidence in seven domains of each study. Prevalence ratios with 95% confidence intervals were calculated and compared in forest plots across studies. Study heterogeneity did not permit formal meta-analyses with pooled results. There was a lack of publications on the primary outcomes, atherosclerotic CVDs (n = 2). Limited evidence of varying consistency from 13 studies in five countries reported that compared with non-agricultural workers, mainly living in urban areas, rural agriculture workers had a lower prevalence of hypertension, overweight and obesity; and a higher prevalence of underweight and smoking. High quality evidence is lacking on the associations of engaging in and transitioning out of agriculture with atherosclerotic CVDs and their modifiable risk factors in LMICs. There is a need for interdisciplinary longitudinal studies to understand associations of types of employment and labour-force transitions with CVD burdens in LMICs.

Urinary Sodium Excretion, Blood Pressure, and Risk of Future Cardiovascular Disease and Mortality in Subjects Without Prior Cardiovascular Disease

Hypertension is a risk factor for cardiovascular disease. Increased urinary sodium excretion, representing dietary sodium intake, is associated with hypertension. Low sodium intake has been associated with increased mortality in observational studies. Further studies should assess whether confounding relationships explain associations between sodium intake and outcomes. We studied UK Biobank participants (n=457 484; mean age, 56.3 years; 44.7% men) with urinary electrolytes and blood pressure data. Estimated daily urinary sodium excretion was calculated using Kawasaki formulae. We analyzed associations between sodium excretion and blood pressure in subjects without cardiovascular disease, treated hypertension, or diabetes mellitus at baseline (n=322 624). We tested relationships between sodium excretion, incidence of fatal and nonfatal cardiovascular disease, heart failure, and mortality. Subjects in higher quintiles of sodium excretion were younger, with more men and higher body mass index. There was a linear relationship between increasing urinary sodium excretion and blood pressure. During median follow-up of 6.99 years, there were 11 932 deaths (1125 cardiovascular deaths) with 10 717 nonfatal cardiovascular events. There was no relationship between quintile of sodium excretion and outcomes. These relationships were unchanged after adjustment for comorbidity or excluding subjects with events during the first 2 years follow-up. No differing risk of incident heart failure (1174 events) existed across sodium excretion quintiles. Urinary sodium excretion correlates with elevated blood pressure in subjects at low cardiovascular risk. No pattern of increased cardiovascular disease, heart failure, or mortality risk was demonstrated with either high or low sodium intake.

The association between family members' migration and Epstein-Barr virus antibody titers among people left behind in rural Fujian, China

OBJECTIVES

In contrast to the health of migrants, which has been extensively studied, little attention has been paid to the health of adults left behind by family members who out-migrated to other locations. This study was performed to investigate the association between being left behind and the Epstein-Barr virus (EBV) antibody titer, which is an indicator of cellular immune functioning previously shown to be associated with psychological stress.

METHODS

A cross-sectional survey was conducted in rural communities in Fujian, China, in 2015. Questionnaire data and dried blood spot samples were collected from 748 adults. A mixed effect regression analysis was conducted to investigate the association.

RESULTS

Results indicated that the EBV antibody titers were higher among people who had been left behind compared with those who had not.

CONCLUSIONS

Our findings suggest that, in rural Fujian, China, family separation following the out-migration of family members is an important determinant of psychological stress.

Cross-Sectional Study on the Management and Control of Hypertension Among Migrants in Primary Care: What Is the Impact of Segmented Health Insurance Schemes?

Background Information is scarce regarding the impact of fragmented health insurance schemes on the management and control of hypertension among migrants in primary care. This study aimed to investigate the relationship between insurance status and management and control of hypertension among migrants in primary care and to examine whether social capital could facilitate migrants' participation in local health insurance schemes. Methods and Results A site-based, cross-sectional, face-to-face patient survey was administered in Shenzhen, China. Hypertensive primary care users who were migrants were selected using a systematic sampling design. The participants covered by local health insurance schemes were more likely than those without coverage to be managed by primary care facilities (82.6% versus 62.0%; odds ratio=2.63, 95% CI 1.41-4.89) and to take antihypertensive medications (87.9% versus 76.4%; odds ratio=2.38, 95% CI 1.34-4.24), and they had higher scores in first contact use (3.49 versus 3.23; β=0.17, 95% CI 0.05-0.29) and continuity of care (3.17 versus 3.02; β=0.11, 95% CI 0.01-0.21). The participants covered by local insurance schemes had higher scores in perceived generalized trust than their counterparts (4.23 versus 3.95; β=0.16, 95% CI 0.09-0.40). The hypertension control rate was also higher among the participants with local health insurance coverage (48.8% versus 42.2%; odds ratio=1.38, 95% CI 1.02-2.12). Conclusions In conclusion, local health insurance schemes are associated with optimal control of hypertension for migrants compared with social health insurance schemes. Our study implies that one form of social capital, namely perceived general trust, contributes to migrant hypertensive patients' participation in local health insurance schemes.

Twenty-year time trends in hypertension prevalence in Yi people of China: three successive cross-sectional studies, 1996-2015

OBJECTIVE

To explore the trend of hypertension prevalence and related factors in Yi people from 1996 to 2015.

METHODS

Three successive cross-sectional surveys were conducted in Liangshan Yi Autonomous Prefecture in 1996, 2007 and 2015, respectively. A total of 8448 participants aged 20-80 years (5040 Yi farmers, 3408 Yi migrants) were included in final analysis.

RESULTS

Overall, the age-standardised prevalence of hypertension in migrants was significantly higher than in farmers. Furthermore, the age-standardised prevalence rates increased from 10.1% to 15.3% to 19.6% in Yi migrants and from 4.0% to 6.3% to 13.1% in Yi farmers during 1996 to 2007 to 2015. The highest 2015-to-1996 ratio of age-standardised hypertension prevalence was in male farmers (ratio=4.30), whereas despite the highest prevalence of hypertension, the equivalent figure in male migrants was 1.57. The older age, overweight and obesity were persistent risk factors of hypertension in three periods. After adjusted for age and body mass index, the difference of hypertension prevalence between 1996 and 2015 then vanished in male migrants (OR=1.335; 95% CI: 0.884 to 2.015) and female farmers (OR=1.267; 95% CI: 0.590 to 2.719). The disparities of hypertension prevalence between Yi migrants and farmers were not statistically significant in all subgroups when adjusted for age, body mass index and education.

CONCLUSIONS

Over the past two decades, the hypertension prevalence in Yi people has significantly increased. Yi migrants were more likely to be hypertensive than Yi farmers which was predominantly driven by the discrepancy of body mass index between them.

Increasing prevalence of overweight and obesity in Yi farmers and migrants from 2007 to 2015 in China: the Yi migrant study

Background

With the social development and lifestyle transition, increasing trends of overweight and obesity prevalence are commonly reported worldwide. Data focusing on overweight and obesity trends in rural residents and rural-to-urban migrants in China are limited. This study aims to assess the changes and related factors of overweight and obesity in Yi farmers and migrants in southwest China from 2007 to 2015, and to assess the disparities in prevalence changes.

Methods

Pseudo-panel data was obtained from two cross-sectional studies conducted in Sichuan province, southwest China in 2007 and 2015. Standardized prevalence of overweight and obesity were evaluated by direct method using the 2010 national census population as the standard. Prevalence differences of overweight and obesity were calculated in each group and compared between groups to evaluate the disparity in prevalence changes. Generalized linear mixed model was performed to determine factors related to overweight/obesity.

Results

Standardized prevalence of overweight increased in both groups (from 5.54 to 16.65% in Yi farmers, from 27.91 to 33.61% in Yi migrants). Standardized prevalence of obesity increased only in Yi farmers (from 0.37 to 3.13%). Prevalence difference of overweight in Yi farmers was higher than that in Yi migrants (11.11 vs. 5.70), but prevalence differences of obesity were not significantly different between Yi farmers and migrants.

Conclusions

Prevalence of overweight and obesity in Yi farmers, and prevalence of overweight in Yi migrants increased from 2007 to 2015. Yi farmers were developing overweight at a greater pace than migrants. More attention should be paid to spread health knowledge and encourage healthy lifestyle in Yi people, especially Yi farmers.

Electronic supplementary material

The online version of this article (10.1186/s12889-018-5577-4) contains supplementary material, which is available to authorized users.

Hypertension

Systemic arterial hypertension is the most important modifiable risk factor for all-cause morbidity and mortality worldwide and is associated with an increased risk of cardiovascular disease (CVD). Fewer than half of those with hypertension are aware of their condition, and many others are aware but not treated or inadequately treated, although successful treatment of hypertension reduces the global burden of disease and mortality. The aetiology of hypertension involves the complex interplay of environmental and pathophysiological factors that affect multiple systems, as well as genetic predisposition. The evaluation of patients with hypertension includes accurate standardized blood pressure (BP) measurement, assessment of the patients' predicted risk of atherosclerotic CVD and evidence of target-organ damage, and detection of secondary causes of hypertension and presence of comorbidities (such as CVD and kidney disease). Lifestyle changes, including dietary modifications and increased physical activity, are effective in lowering BP and preventing hypertension and its CVD sequelae. Pharmacological therapy is very effective in lowering BP and in preventing CVD outcomes in most patients; first-line antihypertensive medications include angiotensin-converting enzyme inhibitors, angiotensin II receptor blockers, dihydropyridine calcium-channel blockers and thiazide diuretics.

The association of estimated salt intake with blood pressure in a Viet Nam national survey

OBJECTIVE

To evaluate the association of salt consumption with blood pressure in Viet Nam, a developing country with a high level of salt consumption.

DESIGN AND SETTING

Analysis of a nationally representative sample of Vietnamese adults 25-65 years of age who were surveyed using the World Health Organization STEPwise approach to Surveillance protocol. Participants who reported acute illness, pregnancy, or current use of antihypertensive medications were excluded. Daily salt consumption was estimated from fasting mid-morning spot urine samples. Associations of salt consumption with systolic blood pressure and prevalent hypertension were assessed using adjusted linear and generalized linear models. Interaction terms were tested to assess differences by age, smoking, alcohol consumption, and rural/urban status.

RESULTS

The analysis included 2,333 participants (mean age: 37 years, 46% male, 33% urban). The average estimated salt consumption was 10g/day. No associations of salt consumption with blood pressure or prevalent hypertension were observed at a national scale in men or women. The associations did not differ in subgroups defined by age, smoking, or alcohol consumption; however, associations differed between urban and rural participants (p-value for interaction of urban/rural status with salt consumption, p = 0.02), suggesting that higher salt consumption may be associated with higher systolic blood pressure in urban residents but lower systolic blood pressure in rural residents.

CONCLUSIONS

Although there was no evidence of an association at a national level, associations of salt consumption with blood pressure differed between urban and rural residents in Viet Nam. The reasons for this differential association are not clear, and given the large rate of rural to urban migration experienced in Viet Nam, this topic warrants further investigation.

Is Migration Affecting Prevalence, Awareness, Treatment and Control of Hypertension of Men in Kerala, India?

We assessed hypertension prevalence, awareness, treatment and control among male gulf migrant and non-migrant workers in Kerala state of India. We did a cross sectional survey of 191 migrant and 193 non-migrant men aged 25-64 years selected using a multistage random sampling method. Using World Health Organization STEPS approach, we collected information on demographics, STEP 1 variables and measured STEP-2 variables. Multivariate analysis was used to find the relation between migration and hypertension. Age adjusted hypertension prevalence was 57.6 % among migrants and 31.7 % among non-migrants (p < 0.05). Migrants were more likely to be hypertensive (OR 3.00, 95 % CI 1.83-4.94) than non-migrants after adjusting for age, STEP 1 and STEP 2 variables. Though not statistically significant (p = 0.109), awareness of hypertension was lower among migrants (43.5 %) compared to non migrants (56.9 %). Treatment (migrants: 34 %, non-migrants: 53 %, p < 0.05) and control (migrants: 12 %, non-migrants: 48 %, p < 0.001) of hypertension were lower among migrants. Greater attention to improve the treatment and control of hypertension among migrants is warranted in this population.

Does Migration Limit the Effect of Health Insurance on Hypertension Management in China?

Background: In China, rapid urbanization has caused migration from rural to urban areas, and raised the prevalence of hypertension. However, public health insurance is not portable from one place to another, and migration may limit the effectiveness of this non-portable health insurance on healthcare. Our study aims to investigate whether migration limits the effectiveness of health insurance on hypertension management in China. Methods: Data were obtained from the national baseline survey of the China Health and Retirement Longitudinal Study in 2011, including 4926 hypertensive respondents with public health insurance. Outcome measures included use of primary care, hypertension awareness, medication use, blood pressure monitoring, physician advice, and blood pressure control. Multivariate logistic regressions were estimated to examine whether the effects of rural health insurance on hypertension management differed between those who migrated to urban areas and those who did not migrate and lived in rural areas. Results: Among hypertensive respondents, 60.7% were aware of their hypertensive status. Compared to rural residents, the non-portable feature of rural health insurance significantly reduced rural-to-urban migrants’ probabilities of using primary care by 7.8 percentage points, hypertension awareness by 8.8 percentage points, and receiving physician advice by 18.3 percentage points. Conclusions: In China, migration to urban areas limited the effectiveness of rural health insurance on hypertension management due to its non-portable nature. It is critical to improve the portability of rural health insurance, and to extend urban health insurance and primary care coverage to rural-to-urban migrants to achieve better chronic disease management.

Smoking and heavy drinking patterns in rural, urban and rural-to-urban migrants: the PERU MIGRANT Study

Background

Previous studies have found mixed results about cigarette and alcohol consumption patterns among rural-to-urban migrants. Moreover, there are limited longitudinal data about consumption patterns in this population. As such, this study aimed to compare the smoking and heavy drinking prevalence among rural, urban, and rural-to-urban migrants in Peru, as well as the smoking and heavy drinking incidence in a 5-year follow-up.

Methods

We analyzed the PERU MIGRANT Study data from rural, urban, and rural-to-urban migrant populations in Peru. The baseline study was carried out in 2006–2007 and follow-up was performed five years later. For the baseline data analysis, the prevalence of lifetime smoking, current smokers, and heavy drinking was compared by population group using prevalence ratios (PR) and 95% confidence intervals (95% CI). For the longitudinal analysis, the incidence of smoking and heavy drinking was compared by population group with risk ratios (RR) and 95% CI. Poisson regression with robust variance was used to calculate both PRs and RRs.

Results

We analyzed data from 988 participants: 200 rural dwellers, 589 migrants, and 199 urban dwellers. Compared with migrants, lifetime smoking prevalence was higher in the urban group (PR = 2.29, 95% CI = 1.64–3.20), but lower in the rural group (PR = 0.55, 95% CI = 0.31–0.99). Compared with migrants, the urban group had a higher current smoking prevalence (PR = 2.29, 95% CI = 1.26–4.16), and a higher smoking incidence (RR = 2.75, 95% CI = 1.03–7.34). Current smoking prevalence and smoking incidence showed no significant difference between rural and migrant groups. The prevalence and incidence of heavy drinking was similar across the three population groups.

Conclusions

Our results show a trend in lifetime smoking prevalence (urban > migrant > rural), while smoking incidence was similar between migrant and rural groups, but higher in the urban group. In addition, our results suggest that different definitions of smoking status could lead to different smoking rates and potentially different measures of association. The prevalence and incidence of heavy drinking were similar between the three population groups.

Electronic supplementary material

The online version of this article (doi:10.1186/s12889-017-4080-7) contains supplementary material, which is available to authorized users.

Rural-to-urban migration and risk of hypertension: longitudinal results of the PERU MIGRANT study

Urbanization can be detrimental to health in populations due to changes in dietary and physical activity patterns. The aim of this study was to determine the effect of migration on the incidence of hypertension. Participants of the PERU MIGRANT study, that is, rural, urban and rural-to-urban migrants, were re-evaluated after 5 years after baseline assessment. The outcome was incidence of hypertension; and the exposures were study group and other well-known risk factors. Incidence rates, relative risks (RRs) and population attributable fractions (PAFs) were calculated. At baseline, 201 (20.4%), 589 (59.5%) and 199 (20.1%) participants were rural, rural-to-urban migrant and urban subjects, respectively. Overall mean age was 47.9 (s.d.±12.0) years, and 522 (52.9%) were female. Hypertension prevalence at baseline was 16.0% (95% confidence interval (CI) 13.7-18.3), being more common in urban group; whereas pre-hypertension was more prevalent in rural participants (P<0.001). Follow-up rate at 5 years was 94%, 895 participants were re-assessed and 33 (3.3%) deaths were recorded. Overall incidence of hypertension was 1.73 (95%CI 1.36-2.20) per 100 person-years. In multivariable model and compared with the urban group, rural group had a greater risk of developing hypertension (RR 3.58; 95%CI 1.42-9.06). PAFs showed high waist circumference as the leading risk factor for the hypertension development in rural (19.1%), migrant (27.9%) and urban (45.8%) participants. Subjects from rural areas are at higher risk of developing hypertension relative to rural-urban migrant or urban groups. Central obesity was the leading risk factor for hypertension incidence in the three population groups.

Probit Models to Investigate Prevalence of Total Diagnosed and Undiagnosed Diabetes among Aged 45 Years or Older Adults in China

The aims of this study are to identify the most important predictors of total diagnosed and undiagnosed diabetes and estimate the mean change in the predicted probability among aged 45+ adults in China. We used baseline data collected from 2011 wave of the China Health and Retirement Longitudinal Study (CHARLS) (n = 9,513). First, we estimated the prevalence of diagnosed, measured, total diagnosed, and undiagnosed diabetes. Second, we used probit models to determine whether individual attributes, socioeconomic characteristics and behavioral health factors, including smoking, alcohol consumption, obesity, central obesity, are associated with total diagnosed and undiagnosed diabetes. We also consider other factors, including contact with medical system, hypertension and urban/rural settings. Third, we estimated average marginal effects of variables in probit models. Among Chinese people aged 45+, the prevalence of diagnosed, measured, total diagnosed and undiagnosed diabetes were 5.8% (95%CI, 5.3%-6.3%), 14.7% (95%CI, 14.0%-15.4%), 17.0% (95%CI, 16.3%-17.7%), 11.3% (95%CI, 10.6%-12.0%), respectively. The probability of total diagnosed diabetes is 3.3% (95% CI, 1.2%-5.3%) and 10.2% (95% CI, 7.0%-13.5%) higher for overweight and obesity than normal BMI, 5.0% (95% CI, 3.0%-7.1%) higher for central obesity than normal waist circumference, 5.4% (95% CI, 3.7%-7.0%) higher for hypertensive than normotensive and 1.8% (95% CI, 0.8%- 2.7%) higher in urban areas than in rural areas, respectively. The probability of undiagnosed diabetes is 2.7% (95% CI, 1.2%-4.2%) and 7.2% (95% CI, 4.7%-9.6%) higher for overweight and obesity than normal BMI, 2.6% (95% CI, 0.9%-4.4%) higher for central obesity than normal waist circumference and 2.6% (95% CI, 1.2%-4.0%) higher for hypertensive than normotensive, respectively, and -1.5% (95% CI, -2.5% to -0.5%) lower for individuals who were in contact with the medical system. Greater focus on prevention of diabetes is necessary for obesity, central obesity, hypertensive and in urban areas for middle-aged and older in China.

Spatiotemporal variation in diabetes mortality in China: multilevel evidence from 2006 and 2012

Background

Despite previous studies reporting spatial in equality in diabetes prevalence across China, potential geographic variations in diabetes mortality have not been explored.

Methods

Age and gender stratified annual diabetes mortality counts for 161 counties were extracted from the China Mortality Surveillance System and interrogated using multilevel negative binomial regression. Random slopes were used to investigate spatiotemporal variation and the proportion of variance explained was used to assess the relative importance of geographical region, urbanization, mean temperature, local diabetes prevalence, behavioral risk factors and relevant biomarkers.

Results

Diabetes mortality tended to reduce between 2006 and 2012, though there appeared to be an increase in diabetes mortality in urban (age standardized rate (ASR) 2006–2012: 10.5–13.6) and rural (ASR 10.8–13.0) areas in the Southwest region. A Median Rate Ratio of 1.47, slope variance of 0.006 (SE 0.001) and covariance of 0.268 (SE 0.007) indicated spatiotemporal variation. Fully adjusted models accounted for 37 % of this geographical variation, with diabetes mortality higher in the Northwest (RR 2.55, 95 % CI 1.74, 3.73) and Northeast (RR 2.68, 95 % CI 1.70, 4.21) compared with the South. Diabetes mortality was higher in urbanized areas (RR tertile 3 versus tertile 1 (‘RRt3vs1’) 1.39, 95 % CI 1.17, 1.66), with higher mean body mass index (RRt3vs1 1.46, 95 % CI 1.18, 1.80) and with higher average temperatures (RR 1.05 95 % CI 1.03, 1.08). Diabetes mortality was lower where consumption of alcohol was excessive (RRt3vs1 0.84, 95 % CI 0.72, 0.99). No association was observed with smoking, overconsumption of red meat, high mean sedentary time, systolic blood pressure, cholesterol, and diabetes prevalence.

Conclusions

Declines in diabetes mortality between 2006 and 2012 have been unequally distributed across China, which may imply differentials in diagnosis, management, and the provision of services that warrant further investigation.

Electronic supplementary material

The online version of this article (doi:10.1186/s12889-015-1982-0) contains supplementary material, which is available to authorized users.

Prevalence of Obesity and Related Factors among Bouyei and Han Peoples in Guizhou Province, Southwest China

OBJECTIVE

To investigate the prevalence of general and abdominal obesity and associated factors in Bouyei and Han peoples.

DESIGN

A cross-sectional study was carried out in Guizhou province, southwest China in 2012, with multi-stage sampling to enroll 4551 participants aged 20 to 80 years. General and abdominal obesity were defined by World Health Organization (WHO) for Chinese. A design-based analysis was performed to evaluate prevalence of obesity and its related factors.

RESULTS

Bouyei people had a significantly lower prevalence of general obesity (4.8% vs. 10.9%, p < 0.05) and abdominal obesity (13.6% vs. 26.8%, p < 0.05) than that in Han people. Prevalence of obesity increased with age until middle-age period and declined thereafter. Men aged 40-49 years group and women aged 50-59 years group have the highest prevalence of general obesity. Prevalence of abdominal obesity was higher than that of general obesity. Middle-age, Higher income, Han people were significantly associated with an increased risk of General/abdominal obesity.

CONCLUSIONS

Bouyei people had a lower prevalence of general and abdominal obesity than the Han people. Etiological studies should be conducted to determine underlying genetic factors and dietary factors.

Prevalence and Factors Associated to Hypertension Among Older Adults in Bogotá, Colombia

Objective: To characterize older adults in Bogotá with high blood pressure and identify factors associated to this condition within this population. Method: Using data from the Salud, Bienestar y Envejecimiento (SABE) (Health, Well-being and Aging) Bogotá Study, we analyzed community-dwelling adults 60 years and older with hypertension. We estimated the prevalence and used logistic regression models to identify factors associated to hypertension. Results: The overall prevalence for hypertension was 56.9%. Older age (odds ratio [OR] = 1.46, 95% confidence interval [CI] = [1.07, 1.97]), having health insurance (OR = 4.15, CI = [1.95, 8.85]), cardiovascular diseases (ORs between 1.70 and 3.65), and poor self-rated health (OR = 1.57, CI = [1.20,2.06]) significantly increased the odds of hypertension. Most individuals received pharmacologic treatment (93.5%); however, 28.4% of individuals had uncontrolled hypertension. Discussion: We found a high prevalence of hypertension in our cohort and found that comorbidities and poor self-rated health increase the odds of hypertension. Future studies need to tailor interventions for hypertension management in old age.

Hypertension prevalence, awareness, treatment and control among Han and four ethnic minorities (Uygur, Hui, Mongolian and Dai) in China

In the previous study, hypertension prevalence, awareness, treatment and control for Han and others four ethnic minorities (Uygur, Hui, Mongolian and Dai) has not been clearly documented in China. Therefore we used the baseline data of Prospective Urban and Rural Epidemiology (PURE) for further detailed study. Adjusted rate were estimated and compared through logistic regression after adjustment of age, sex, location and education. Among the total of 7137 participants (Han: 1626, ethnic minorities: 5511), hypertension prevalence, awareness, treatment and control were 2922(40.9%), 1199(41.0%), 873(29.9%) and 147(5.0%), respectively. The most commonly used antihypertensive drugs are traditional compound drugs (6.2%) and calcium channel blockers (5.2%). Hypertension prevalence in ethnic minorities was significantly higher than in Han (42.4% vs 34.4%, P<0.0001), while control rate (1.6% vs 9.8%, P=0.0198) and treated control rate (8.0% vs 25.0%, P=0.0200) were lower. Compared with Han counterparts, Dai had a higher prevalence (50.8% vs 29.9%, P<0.0001). Uygur had a lower treatment rate (33.2% vs 20.6%, P=0.0110). Mongolian had a lower control (5.1% vs 16.1%, P=0.0046) and treated control rate (14.1% vs 50.3%, P=0.0013). In conclusions, our study showed ethnic minorities had higher hypertension prevalence, especially for Dai and lower control and treated control rate for Mongolian. Hence, we need more attention with respect to hypertension in ethnic minorities.

Modifiable Risk factors of Hypertension and Socio-demographic Profile in Oghara, Delta State; Prevalence and Correlates

BACKGROUND

Factors associated with the development of hypertension can be categorized into modifiable and non-modifiable risk factors. The modifiable risk factors include obesity, physical inactivity, high salt diet, smoking alcohol consumption and others.

AIM

This study was aimed to determine the prevalence of modifiable risk factors of hypertension in a rural community; Oghara and to ascertain if any association exists with these risk factors and socio-demographic variables.

SUBJECTS AND METHODS

Descriptive cross-sectional study design was utilized for the study and it was carried out over a period of 6 months (Feburary 2012 to August 2012). Cluster sampling was utilized to select a total of 272 respondents for the study. An interviewer administered questionnaire was used to collect data and data analysis was performed by SPSS version 16.0 (Chicago II, USA).

RESULTS

The prevalence of hypertension is 21.0% (57/272), while the prevalence of modifiable risk factors of hypertension such as smoking, alcohol consumption and obesity are 15.8% (43/272), 43.4% (118/272) and 18.8% (51/272) respectively. There is a statistical significant association between hypertension and smoking (P < 0.001), as well as hypertension and alcohol. (P < 0.001), on the other hand socio-demographic variables were significantly associated with smoking (P < 0.001).

CONCLUSION

The study showed high prevalence of modifiable risk factors of hypertension. This underscores the need for preventive efforts to encourage changes in life style pattern in order to reverse the impending epidemic of hypertension and other non-communicable diseases.

Dietary salt intake and hypertension

Over the past century, salt has been the subject of intense scientific research related to blood pressure elevation and cardiovascular mortalities. Moderate reduction of dietary salt intake is generally an effective measure to reduce blood pressure. However, recently some in the academic society and lay media dispute the benefits of salt restriction, pointing to inconsistent outcomes noted in some observational studies. A reduction in dietary salt from the current intake of 9-12 g/day to the recommended level of less than 5-6 g/day will have major beneficial effects on cardiovascular health along with major healthcare cost savings around the world. The World Health Organization (WHO) strongly recommended to reduce dietary salt intake as one of the top priority actions to tackle the global non-communicable disease crisis and has urged member nations to take action to reduce population wide dietary salt intake to decrease the number of deaths from hypertension, cardiovascular disease and stroke. However, some scientists still advocate the possibility of increased risk of CVD morbidity and mortality at extremes of low salt intake. Future research may inform the optimal sodium reduction strategies and intake targets for general populations. Until then, we have to continue to build consensus around the greatest benefits of salt reduction for CVD prevention, and dietary salt intake reduction strategies must remain at the top of the public health agenda.

Influence of living arrangements on the management and control of hypertension: a mixed-methods study of Korean American elderly

Elders living alone may experience worse health outcomes than do those living with spouse and/or children. Using baseline data from a randomized trial to promote high blood pressure (HBP) control in Korean elders (N = 440), we examined the relationship between living arrangements and HBP control. We also interviewed a sub-sample to better understand the patterns of social interactions associated with different types of living arrangements. One in five reported living alone; this group tended to be older and female, and resided in senior group housing. Those living alone were twice as likely as those living with a spouse to have controlled BP (OR = 2.08; 95 % CI 1.09-3.97), even after controlling for study covariates. Those in senior group housing had frequent social interactions that involved conversations around health, encouragement concerning medication taking, and health information sharing. In conclusion, Korean elders living independently are neither socially-isolated nor at increased risk for poor BP control.

Beyond the clinic: importance of community involvement in sodium-reduction efforts

Excessive sodium intake is a serious public health problem that is amenable to intervention. Despite campaigns that often target individuals to encourage lower sodium intake, consumption is far in excess of recommendations. There is increasing recognition of the importance of the food environment in shaping dietary behavior and the need for strategies that focus on changing community-level environmental factors that support a shift in behavior toward more healthful eating. Practice-based evidence should be coupled with evidence from well-conducted clinical studies of sodium and health to build the foundation for public health interventions that achieve and sustain sodium reduction in the general population. This article discusses the importance of moving beyond the clinic and engaging communities in this important public health effort.

Hypertension: physiology and pathophysiology

Despite major advances in understanding the pathophysiology of hypertension and availability of effective and safe antihypertensive drugs, suboptimal blood pressure (BP) control is still the most important risk factor for cardiovascular mortality and is globally responsible for more than 7 million deaths annually. Short-term and long-term BP regulation involve the integrated actions of multiple cardiovascular, renal, neural, endocrine, and local tissue control systems. Clinical and experimental observations strongly support a central role for the kidneys in the long-term regulation of BP, and abnormal renal-pressure natriuresis is present in all forms of chronic hypertension. Impaired renal-pressure natriuresis and chronic hypertension can be caused by intrarenal or extrarenal factors that reduce glomerular filtration rate or increase renal tubular reabsorption of salt and water; these factors include excessive activation of the renin-angiotensin-aldosterone and sympathetic nervous systems, increased formation of reactive oxygen species, endothelin, and inflammatory cytokines, or decreased synthesis of nitric oxide and various natriuretic factors. In human primary (essential) hypertension, the precise causes of impaired renal function are not completely understood, although excessive weight gain and dietary factors appear to play a major role since hypertension is rare in nonobese hunter-gathers living in nonindustrialized societies. Recent advances in genetics offer opportunities to discover gene-environment interactions that may also contribute to hypertension, although success thus far has been limited mainly to identification of rare monogenic forms of hypertension.

Age, period and cohort effects on adult body mass index and overweight from 1991 to 2009 in China: the China Health and Nutrition Survey

BACKGROUND

Contributions of age-period-cohort effects to increases in BMI and overweight among Chinese adults must be resolved in order to design appropriate interventions. The objectives were to (i) describe the period effect on BMI and overweight among Chinese adults from 1991 to 2009 and assess modification of this effect by age (e.g. cohort effect) and gender, and (ii) quantify the influence of household income and community urbanicity on these effects.

METHODS

Data are from the China Health and Nutrition Survey, a prospective sample across nine provinces in China; 53,298 observations from 18,059 participants were collected over a 19-year period. A series of mixed effects models was used to explicitly assess differences in BMI within individuals over time (age effect) and population-wide differences in BMI over time (period effect), and implicitly assess differences in the experienced period effect across individuals of varying ages (cohort effect).

RESULTS

Stronger period effects on BMI and overweight were observed among males compared with females; and younger cohorts had higher BMIs compared with older cohorts. Simulations predicted that increases in income and urbanicity in the order of magnitude of that observed from 1991 to 2009 would correspond to shifts in the BMIs of average individuals of 0.07 and 0.23 kg/m(2), respectively.

CONCLUSIONS

Although period effects had a stronger influence on the BMI of males, interventions should not overlook younger female cohorts who are at increased risk compared with their older counterparts.

Blood pressure and levels of Fe, Ca, Mg, Zn, Cu, Na and K in the hair of young Bantu men from Tanzania

Mineral imbalance in the body may significantly contribute to the development and course of hypertension. In this paper, blood pressure figures have been linked to the levels of Fe, Ca, Mg, Zn, Cu, Na and K in hair. The research sample was composed of young men (n = 91) aged 13-21, from the town of Mafinga, Iringa District, Tanzania. The data collected included their age, tribal background and weekly diet. Based on body mass index, the participants were categorised into pre-defined subgroups. To examine how the minerals in question affect blood pressure, correlation analysis and multiple ridge regression analysis were performed. Analysis of ridge regression findings for the researched group (n = 91) shows that the minerals under scrutiny account for systolic blood pressure variation in 13 % and in 15 % for diastolic blood pressure variation. After including two additional variables-calendar age and body mass index-in regression analysis, the ultimate coefficient of determination (R (2)) changes for systolic blood pressure and remains the same for diastolic blood pressure (R (2) = 0.194 and R (2) = 0.156, respectively). Nutritional analysis shows that the students included in the study received insufficient calories per day (1,500-2,200 kcal). The group of students with abnormal blood pressure were not aware of their poor health. Research findings may result from progressive environmental changes and poor nutrition in terms of food quantity and quality, which had an impact on the subjects' blood pressure. Hair analysis used to determine mineral content in the body may be an auxiliary tool in identifying the links between factors leading to the development of hypertension.

Health of China's rural-urban migrants and their families: a review of literature from 2000 to 2012

BACKGROUND

Socioeconomic transformation in China at the beginning of the twenty-first century has led to rapid urbanization and accelerated rural-urban migration. As a result, the concerns about public health problems triggered by increasing internal population mobility have been more widely studied in recent years.

SOURCES OF DATA

Published data in Chinese and English on health of migrants and their families in mainland China from 2000 to 2012.

AREAS OF AGREEMENT

The shifting patterns of disease distribution due to rural-urban migration, health equity and health reform strategies that cater for this specific yet substantial subpopulation are outstanding concerns. Infectious diseases, mental health, occupational health and women's health are emerging public health priorities related to migration.

AREAS OF CONTROVERSY

The high mobility and large numbers of Chinese rural-urban migrants pose challenges to research methods and the reliability of evidence gained.

GROWING POINTS

While the theme of working migrants is common in the literature, there have also been some studies of health of those left behind but who often remain unregistered. Migration within China is not a single entity and understanding the dynamics of new and emerging societies will need further study.

AREAS TIMELY FOR DEVELOPING RESEARCH

Social, economic, emotional, environmental and behavioural risk factors that impact on health of migrants and their families call for more attention from health policy-makers and researchers in contemporary China.

Convergence of non-communicable and infectious diseases in low- and middle-income countries

The convergence of non-communicable disease (NCD) and infectious disease (ID) in low- and middle-income countries (LMICs) presents new challenges and new opportunities to enact responsive changes in policy and research. Most LMICs have significant dual disease burdens of NCDs such as cardiovascular disease, diabetes and cancer, and IDs including tuberculosis, HIV/AIDS and parasitic diseases. A combined strategy is needed in surveillance and disease control; yet, experts, institutions and policies that support prevention and control of these two overarching disease categories have limited interaction and alignment. NCDs and IDs share common features, such as long-term care needs and overlapping high-risk populations, and there are also notable direct interactions, such as the association between certain IDs and cancers, as well as evidence of increased susceptibility to IDs in individuals with NCDs. Enhanced simultaneous surveillance of NCD and ID comorbidity in LMIC populations would generate the empirical data needed to better understand the dual burden, and to target coordinated care. Where IDs and NCDs are endemic, focusing on vulnerable populations by strengthening social protections and improving access to health services is crucial, as is the re-alignment of efforts to combine NCD and ID screening, treatment programmes, and the assessment of their impact. Integrating public health activities for ID and NCD should extend beyond health care services to prevention, which is widely seen as crucial to successful NCD and ID control campaigns alike. The convergence of NCD and ID in LMICs has the potential to overstretch already strained health systems. With some LMICs now focused on major health system reforms, a unique opportunity is available to address NCD and ID challenges with newfound urgency and novel approaches.

Projected impact of urbanization on cardiovascular disease in China

OBJECTIVES

The Coronary Heart Disease (CHD) Policy Model-China, a national scale cardiovascular disease computer simulation model, was used to project future impact of urbanization.

METHODS

Populations and cardiovascular disease incidence rates were stratified into four submodels: North-Urban, South-Urban, North-Rural, and South-Rural. 2010 was the base year, and high and low urbanization rate scenarios were used to project 2030 populations.

RESULTS

Rural-to-urban migration, population growth, and aging were projected to more than double cardiovascular disease events in urban areas and increase events by 27.0-45.6% in rural areas. Urbanization is estimated to raise age-standardized coronary heart disease incidence by 73-81 per 100,000 and stroke incidence only slightly.

CONCLUSIONS

Rural-to-urban migration will likely be a major demographic driver of the cardiovascular disease epidemic in China.

Hypertension in developing countries

Data from different national and regional surveys show that hypertension is common in developing countries, particularly in urban areas, and that rates of awareness, treatment, and control are low. Several hypertension risk factors seem to be more common in developing countries than in developed regions. Findings from serial surveys show an increasing prevalence of hypertension in developing countries, possibly caused by urbanisation, ageing of population, changes to dietary habits, and social stress. High illiteracy rates, poor access to health facilities, bad dietary habits, poverty, and high costs of drugs contribute to poor blood pressure control. The health system in many developing countries is inadequate because of low funds, poor infrastructure, and inexperience. Priority is given to acute disorders, child and maternal health care, and control of communicable diseases. Governments, together with medical societies and non-governmental organisations, should support and promote preventive programmes aiming to increase public awareness, educate physicians, and reduce salt intake. Regulations for the food industry and the production and availability of generic drugs should be reinforced.

Sex differences in risk factors for cardiovascular disease: the PERU MIGRANT study

INTRODUCTION

Although men and women have similar risk factors for cardiovascular disease, many social behaviors in developing countries differ by sex. Rural-to-urban migrants have different cardiovascular risk profiles than rural or urban dwellers. The objective of this study was to evaluate the sex differences with specific cardiovascular risk factors in rural-to-urban migrants.

METHODS AND RESULTS

We used the rural-to-urban migrant group of the PERU MIGRANT cross-sectional study to investigate the sex differences in specific cardiovascular risk factors: obesity, hypertension, metabolic syndrome, as well as exposures of socioeconomic status, acculturation surrogates and behavioral characteristics. Logistic regression analysis was used to characterize strength of association between sex and our outcomes adjusting for potential confounders. The sample of migrants was 589 (mean age 46.5 years) and 52.4% were female. In the adjusted models, women were more likely to be obese (OR=5.97; 95%CI: 3.21-11) and have metabolic syndrome (OR=2.22; 95%CI: 1.39-3.55) than men, explaining the greatest variability for obesity and metabolic syndrome but not for hypertension.

CONCLUSIONS

Our results suggest that interventions for CVD in Peru should be sex-specific and address the unique health needs of migrant populations living in urban shantytowns since the risk factors for obesity and metabolic syndrome differ between males and females.

The age associations of blood pressure, cholesterol, and glucose: analysis of health examination surveys from international populations

BACKGROUND

The age association of cardiovascular disease may be in part because its metabolic risk factors tend to rise with age. Few studies have analyzed age associations of multiple metabolic risks in the same population, especially in nationally representative samples. We examined worldwide variations in the age associations of systolic blood pressure (SBP), total cholesterol (TC), and fasting plasma glucose (FPG).

METHODS AND RESULTS

We used individual records from 83 nationally or subnationally representative health examination surveys in 52 countries to fit a linear model to risk factor data between ages 30 and 64 years for SBP and FPG, and between 30 and 54 years for TC. We report the cross-country variation of the slope and intercept of this relationship. We also assessed nonlinear associations in older ages. Between 30 and 64 years of age, SBP increased by 1.7 to 11.6 mm Hg per 10 years of age, and FPG increased by 0.8 to 20.4 mg/dL per 10 years of age in different countries and in the 2 sexes. Between 30 and 54 years of age, TC increased by 0.2 to 22.4 mg/dL per 10 years of age in different surveys and in the 2 sexes. For all risk factors and in most countries, risk factor levels rose more steeply among women than among men, especially for TC. On average, there was a flattening of age-SBP relationship in older ages; TC and FPG age associations reversed in older ages, leading to lower levels in older ages than in middle ages.

CONCLUSIONS

The rise with age of major metabolic cardiovascular disease risk factors varied substantially across populations, especially for FPG and TC. TC rose more steeply in high-income countries and FPG in the Oceania countries, the Middle East, and the United States. The SBP age association had no specific income or geographical pattern.

Hypertension in sub-Saharan Africa: cross-sectional surveys in four rural and urban communities

Background

Cardiovascular disease (CVD) is the leading cause of adult mortality in low-income countries but data on the prevalence of cardiovascular risk factors such as hypertension are scarce, especially in sub-Saharan Africa (SSA). This study aims to assess the prevalence of hypertension and determinants of blood pressure in four SSA populations in rural Nigeria and Kenya, and urban Namibia and Tanzania.

Methods and Findings

We performed four cross-sectional household surveys in Kwara State, Nigeria; Nandi district, Kenya; Dar es Salaam, Tanzania and Greater Windhoek, Namibia, between 2009–2011. Representative population-based samples were drawn in Nigeria and Namibia. The Kenya and Tanzania study populations consisted of specific target groups. Within a final sample size of 5,500 households, 9,857 non-pregnant adults were eligible for analysis on hypertension. Of those, 7,568 respondents ≥18 years were included. The primary outcome measure was the prevalence of hypertension in each of the populations under study.

The age-standardized prevalence of hypertension was 19.3% (95%CI:17.3–21.3) in rural Nigeria, 21.4% (19.8–23.0) in rural Kenya, 23.7% (21.3–26.2) in urban Tanzania, and 38.0% (35.9–40.1) in urban Namibia. In individuals with hypertension, the proportion of grade 2 (≥160/100 mmHg) or grade 3 hypertension (≥180/110 mmHg) ranged from 29.2% (Namibia) to 43.3% (Nigeria). Control of hypertension ranged from 2.6% in Kenya to 17.8% in Namibia. Obesity prevalence (BMI ≥30) ranged from 6.1% (Nigeria) to 17.4% (Tanzania) and together with age and gender, BMI independently predicted blood pressure level in all study populations. Diabetes prevalence ranged from 2.1% (Namibia) to 3.7% (Tanzania).

Conclusion

Hypertension was the most frequently observed risk factor for CVD in both urban and rural communities in SSA and will contribute to the growing burden of CVD in SSA. Low levels of control of hypertension are alarming. Strengthening of health care systems in SSA to contain the emerging epidemic of CVD is urgently needed.

North Korean refugee health in South Korea (NORNS) study: study design and methods

Background

Understanding the health status of North Korean refugees (NKRs), and changes in health during the resettlement process, is important from both the humanitarian standpoint and the scientific perspective. The NOrth Korean Refugee health iN South Korea (NORNS) study aims to document the health status and health determinants of North Korean refugees, to observe various health outcomes as they occur while adapting to the westernized lifestyle of South Korea, and to explain the mechanisms of how health of migrants and refugees changes in the context of new environmental risks and opportunities.

Methods

The NORNS study was composed of an initial survey and a follow-up survey 3.5 years apart. Participants were recruited voluntarily among those aged 30 or more living in Seoul. The survey consists of a health questionnaire and medical examination. The health questionnaire comprises the following six domains: 1) demographic and migration information 2) disease history, 3) mental health, 4) health-related lifestyle, 5) female reproductive health, and 6) sociocultural adaptation. The medical examination comprises anthropometric measurements, blood pressure and atherosclerosis, and various biochemical measurements. Prevalence of several diseases able to be diagnosed from the medical examination, the changes between the two surveys, and the association between the outcome and other measurements, such as length of stay and extent of adaptation in South Korea will be investigated. Furthermore, the outcome will be compared to a South Korean counterpart cohort to evaluate the relative health status of NKRs.

Discussion

The NORNS study targeting adult NKRs in South Korea is a valuable study because various scales and medical measurements are employed for the first time. The results obtained from this study are expected to be utilized for developing a health policy for NKRs and North Korean people after unification. Additionally, since NKRs are an immigrant group who are the same race and have the same genetic characteristics as South Koreans, this study has the characteristics of a unique type of migrant health study.

Urbanisation and health in China

China has seen the largest human migration in history, and the country's rapid urbanisation has important consequences for public health. A provincial analysis of its urbanisation trends shows shifting and accelerating rural-to-urban migration across the country and accompanying rapid increases in city size and population. The growing disease burden in urban areas attributable to nutrition and lifestyle choices is a major public health challenge, as are troubling disparities in health-care access, vaccination coverage, and accidents and injuries in China's rural-to-urban migrant population. Urban environmental quality, including air and water pollution, contributes to disease both in urban and in rural areas, and traffic-related accidents pose a major public health threat as the country becomes increasingly motorised. To address the health challenges and maximise the benefits that accompany this rapid urbanisation, innovative health policies focused on the needs of migrants and research that could close knowledge gaps on urban population exposures are needed.

Migrating husbands and changing cardiovascular risk factors in the wife: a cross sectional study in Asian Indian women

OBJECTIVE

The authors studied the influence of migration of husband on cardiovascular risk factors in Asian Indian women.

METHODS

Population-based studies in women aged 35-70 years were performed in four urban and five rural locations. 4608 (rural 2604 and urban 2004) of the targeted 8000 (57%) were enrolled. Demographic details, lifestyle factors, anthropometry, fasting glucose and cholesterol were measured. Multivariate logistic and quadratic regression was performed to compare influence of migration and its duration on prevalence of risk factors.

RESULTS

Details of migration were available in 4573 women (rural 2267, rural-urban migrants 455, urban 1552 and urban-rural migrants 299). Majority were married, and illiteracy was high. Median (interquartile) duration of residence in urban locations among rural-urban migrants was 9 (4-18) years and in rural areas for urban-rural migrants 23 (18-30) years. In rural, rural-urban migrants, urban and urban-rural migrants, age-adjusted prevalence (%) of risk factors was tobacco use 41.9, 22.7, 18.8 and 38.1; sedentary lifestyle 69.7, 82.0, 79.9 and 74.6; high-fat diet 33.3, 54.2, 66.1 and 61.1; overweight 21.3, 42.7, 46.3 and 29.7; large waist 8.5, 38.5, 29.2 and 29.2; hypertension 30.4, 49.4, 47.7 and 38.4; hypercholesterolaemia 14.4, 31.3, 26.6 and 9.1 and diabetes 3.9, 15.8, 14.9 and 8.4, respectively (p<0.001). In rural-urban migrants, there was a significant correlation of duration of migration with waist size, waist-to-hip ratio and systolic blood pressure (quadratic regression, p<0.001). Association of risk factors with migration remained significant, though attenuated, after adjustment for socioeconomic, lifestyle and obesity variables (logistic regression, p<0.01).

CONCLUSIONS

Compared with rural women, rural-urban migrants and urban have significantly greater cardiometabolic risk factors. Prevalence is lower in urban-rural migrants. There is significant correlation of duration of migration with obesity and blood pressure. Differences are attenuated after adjusting for social and lifestyle variables.

High blood pressure in Chinese ethnic minorities: report from rural Yunnan province

BACKGROUND

Hypertension (HTN) is a growing cause of morbidity and mortality among rural Chinese. While HTN has been studied in various regions of China, little is known about HTN among ethnic minorities in rural China.

METHODS

A total of 36 villages were randomly selected from Yunnan province, China. From these villages, a total of 1,676 subjects from 10 ethnic minorities and the Han ethnic majority were selected for interview and blood pressure (BP) measurement. From each village, 50-80 men and women between the ages of 50 and 70 years were randomly selected. HTN prevalence, treatment, and control rates of HTN were evaluated in these 11 ethnic groups.

RESULTS

After controlling for age, gender, body mass index (BMI), smoking, alcohol, and monosodium glutamate intake, prevalence of HTN varied between 25% in the Hani minority and 64% in the Tibetan minority (P < 0.001). Treatment rates varied between 0% in the Hani minority and 41% in the Tibetan minority (P = 0.006). Control rates varied between 0% in the Hani minority and 17% in the Tibetan minority (P = 0.28). Prevalence, treatment, and control rates in the Han ethnic group were 35, 22, and 12%, respectively.

CONCLUSIONS

The prevalence of HTN varies widely among China's ethnic groups. Treatment and control rates of HTN also vary and are inadequate in the minority ethnic groups as well as in the Han majority.

Effect of rural-to-urban within-country migration on cardiovascular risk factors in low- and middle-income countries: a systematic review

CONTEXT

Limited information is available of effects of rural-to-urban within-country migration on cardiovascular (CV) risk factors in low- and middle- income countries (LMIC).

OBJECTIVE

A systematic review of studies evaluating these effects was performed with rural and/or urban control groups.

STUDY SELECTION

Two teams of investigators searched observational studies in Medline, Web of Science and Scopus until May 2011. Studies evaluating international migration were excluded.

DATA EXTRACTION

Three investigators extracted the information stratified by gender. Information on 17 known CV risk factors was obtained.

RESULTS

Eighteen studies (n=58,536) were included. Studies were highly heterogeneous with respect to study design, migrant sampling frame, migrant urban exposure and reported CV risk factors. In migrants, commonly reported CV risk factors-systolic and diastolic blood pressure, body mass index, obesity, total cholesterol and low-density lipoprotein-were usually higher or more common than in the rural group and usually lower or less common than in the urban group. This gradient was usually present in both genders. Anthropometric (waist-to-hip ratio, hip/waist circumference, triceps skinfolds) and metabolic (fasting glucose/insulin, insulin resistance) risk factors usually followed the same gradient, but conclusions were weak as information was insufficient. Hypertension, high-density lipoprotein, fibrinogen and C-reactive protein did not follow any pattern.

CONCLUSIONS

In LMIC, most but not all, CV risk factors are higher or more common in migrants than in rural groups but lower or less common than in urban groups. Such gradients may or may not be associated with differential CV events and long-term evaluations are necessary.