Body weight and mortality: a prospective evaluation in a cohort of middle-aged men in Shanghai, China

Health consequences of obesity and projected future obesity health burden in China

OBJECTIVE

This study examined the effects of overweight/obesity on mortality and morbidity outcomes and the disparities, time trends, and projected future obesity health burden in China.

METHODS

Cohort studies that were conducted in China and published in English or Chinese between January 1, 1995, and July 31, 2021, were systematically searched. This study focused on overweight/obesity, type 2 diabetes mellitus (T2DM), hypertension, cardiovascular diseases, metabolic syndrome, cancers, and chronic kidney disease.

RESULTS

A total of 31 cohorts and 50 cohort studies reporting on mortality (n = 20) and morbidities (n = 30) associated with obesity met study inclusion criteria. Overall, BMI was nonlinearly (U-shaped) associated with all-cause mortality and linearly associated with risks of T2DM, cardiovascular diseases, hypertension, cancer, metabolic syndrome, and chronic kidney disease. In 2018, among adults, the prevalence of overweight/obesity, hypertension, and T2DM was 51.2%, 27.5%, and 12.4%, respectively. Their future projected prevalence would be 70.5%, 35.4%, and 18.5% in 2030, respectively. The projected number of adults having these conditions would be 810.65 million, 416.47 million, and 217.64 million, respectively. The urban-rural disparity in overweight/obesity prevalence was projected to shrink and then reverse over time.

CONCLUSIONS

The current health burden of obesity in China is high and it will sharply increase in coming years and affect population groups differently. China needs to implement vigorous interventions for obesity prevention and treatment.

Impact of nutrition status and body mass index on mortality in hospitalized general medical patients: A prospective observational study

BACKGROUND

Malnutrition and low body mass index (BMI) are risk factors for mortality in hospitalized patients. Data substantiating this are unavailable for hospitalized general medical patients in our setting. We studied the prevalence of malnutrition among patients admitted to general medical wards in a tertiary care hospital and its role as a risk factor for 1-month mortality. We also investigated the association of BMI with mortality.

METHODS

In this prospective observational study, nutrition assessment using Subjective Global Assessment (SGA) and anthropometric measurements was performed in 395 hospitalized general medical patients. Charlson Comorbidity Index (CCI) and Modified Early Warning System (MEWS) score were calculated. Clinical course and vital status at 1 month after discharge was noted. Factors associated with mortality were identified using logistic regression.

RESULTS

The mean age of the study population was 46.2 + 16.1 years; 247 (62.5%) were males. Of 395 patients, 129 (32.7%) belonged to SGA A, 155 (39.2%) to SGA B, and 111 (28.1%) to SGA C. Mean (±SD) BMI was 23.38 (±5.33); 141 (35.6%) were obese. Mortality was observed in 61 (15.4%) patients. Patients in the lowest BMI quartile had the lowest mortality. The adjusted regression analysis showed that higher age and MEWS scores were independently associated with mortality. Severe malnourishment (SGA C) was another important predictor. Further, the odds of death increased consistently across the consecutive BMI quartiles.

CONCLUSION

Higher age, higher MEWS scores, severe malnourishment, and higher BMI scores were independent risk factors for 1-month mortality in hospitalized general medical patients.

Body mass index trajectories and mortality in community-dwelling older adults: population-based cohort study

OBJECTIVE

Both low and high body mass index (BMI) have been associated with greater mortality in older adults. This study aimed to evaluate the trajectory of BMI in the final years of life.

METHODS

A population-based cohort study was conducted including community-dwelling adults in the English Longitudinal Study of Ageing between 1998 and 2012. BMI was evaluated in relation to age and years before death. Number of long-term conditions, cigarette smoking and socioeconomic position were evaluated as effect modifiers.

RESULTS

Data were analysed for 16 924 participants with 31 857 BMI records; mean age at study starts, 61.6 (SD 10.9) years; mean BMI, 27.5 (4.7) Kg/m². There were 3686 participants (4794 BMI records) who died and 13 238 participants (27 063 BMI records) who were alive at last follow-up. Mean BMI increased with age to 60-69 years but then declined, but the age-related decline was more rapid in decedents. From 4 to 7 years before death or end of study, adjusted mean BMI was 0.87 (95% CI 0.50 to 1.24) Kg/m² lower for male decedents than survivors and 1.02 (0.56 to 1.47) lower in women; and from 3 to 0 years before death, BMI was 1.39 (0.98 to 1.80) Kg/m² lower in male decedents and 2.12 (1.60 to 2.64) lower in female decedents. Multiple long-term conditions and lower socioeconomic position were associated with higher peak BMI and greater BMI decline; current smoking was associated with lower BMI and greater BMI decline.

CONCLUSIONS

In community-dwelling older adults, mean BMI enters an accelerating decline from up to 8 years before death. Multiple long-term conditions, smoking and lower socioeconomic position are associated with BMI decline.

Health policy and public health implications of obesity in China

China has experienced many drastic social and economic changes and shifts in people's lifestyles since the 1990s, in parallel with the fast rising prevalence of obesity. About half of adults and a fifth of children have overweight or obesity according to the Chinese criteria, making China the country with the highest number of people with overweight or obesity in the world. Assuming that observed time trends would continue in the future, we projected the prevalence of and the number of people affected by overweight and obesity by 2030, and the associated medical costs. The rising incidence of obesity and number of people affected, as well as the related health and economic consequences, place a huge burden on China's health-care system. China has made many efforts to tackle obesity, including the implementation of relevant national policies and programmes. However, these measures are inadequate for controlling the obesity epidemic. In the past decade, China has attached great importance to public health, and the Healthy China 2030 national strategy initiated in 2016 provides a historical opportunity to establish comprehensive national strategies for tackling obesity. China is well positioned to explore an effective model to overcome the obesity epidemic; however, strong commitment and leadership from central and local governments are needed, as well as active participation of all related society sectors and individual citizens. TRANSLATION: For the Chinese translation of the paper see Supplementary Materials section.

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.

Relationship Between Body Mass Index and Incidence of Atrial Fibrillation in Young Japanese Men - The Nishimura Health Survey

BACKGROUND

The associations between body mass index (BMI) and incidence of atrial fibrillation (AF) in young men are scarce, especially in Asian countries, given the differences in BMI between Asians and Western populations.Methods and Results:This study analyzed 17,865 middle-aged Japanese men without AF from a cohort of employees undergoing annual health examinations. AF incidence was evaluated during a follow-up period (median 4.0 years, interquartile range 2.0-7.1 years). Among young men aged 30-49 years, AF incidence was 0.64/1,000 person-years, whereas it was 2.54/1,000 and 7.60/1,000 person-years among men aged 50-59 and ≥60 years, respectively. Multivariable Cox regression analysis among young men revealed age (hazard ratio [HR] 3.28 by 10-years' increase, 95% confidence interval [CI] 1.72-6.25, P<0.001), BMI (BMI-quadratic, HR 1.01, 95% CI 1.00-1.01, P<0.001, BMI-linear, HR 0.95, 95% CI 0.86-1.05, P=0.33), and electrocardiogram (ECG) abnormalities, such as PQ prolongation, supraventricular beat, and p wave abnormality (HR 8.79, 95% CI 3.05-25.32, P<0.001), were significantly associated with AF incidence. There was a reverse J-shaped association between BMI and AF incidence in young men, whereby the presence of ECG abnormality inversely influenced the BMI-incident AF relationship. A linear association between BMI and AF incidence in men aged 50-59 and ≥60 years was present.

CONCLUSIONS

AF incidence displays a reverse J-shaped relationship with BMI in young men, but a linear association in men aged ≥50 years. The paradoxical relationship seen in young men only may reflect atrial electrical or structural abnormalities.

Beauty and the Body of the Beholder: Raters' BMI Has Only Limited Association with Ratings of Attractiveness of the Opposite Sex

OBJECTIVE

Assortative mating for adiposity increases the genetic burden on offspring, but its causes remain unclear. One hypothesis is that people who have high adiposity find other people with obesity more physically attractive than lean people.

METHODS

The attractiveness of sets of images of males and females who varied in adiposity were rated by opposite sex subjects (559 males and 340 females) across 12 countries.

RESULTS

There was tremendous individual variability in attractiveness ratings. For female attractiveness, most males favored the leanest subjects, but others favored intermediate fatness, some were indifferent to body composition, and others rated the subjects with obesity as most attractive. For male images rated by females, the patterns were more complex. Most females favored subjects with low levels of adiposity (but not the lowest level), whereas others were indifferent to body fatness or rated the images depicting individuals with obesity as the most attractive. These patterns were unrelated to rater BMI. Among Caucasian males who rated the images of the thinnest females as being more attractive, the magnitude of the effect depended on rater BMI, indicating limited "mutual attraction."

CONCLUSIONS

Individual variations in ratings of physical attractiveness were broadly unrelated to rater BMI and suggest that mutual attraction is an unlikely explanation for assortative mating for obesity.

Age-dependent relationships between body mass index and mortality: Singapore longitudinal ageing study

OBJECTIVES

The relationship between body mass index (BMI) with mortality risk, in particular the BMI category associated with the lowest all-cause and CVD-and-stroke mortality and the BMI threshold for defining overweight or obesity in older persons is controversial. This study investigated the age-dependent associations of BMI categories with all-cause and cardiovascular disease (CVD) and stroke mortality.

METHOD

Prospective cohort study (Singapore Longitudinal Ageing Studies) of older adults aged 55 and above, followed up from 2003 to 2011. Participants were 2605 Chinese with baseline BMI and other variables. Outcome Measurement: Mortality hazard ratios (HR) for all-cause and CVD and stroke mortality.

RESULTS

Overall, BMI showed a U-shaped relationship with all-cause and CVD and stroke mortality, being lowest at Normal Weight-II category (BMI 23.0-24.9 kg/m2). Most evidently among the middle-aged (55-64 years), all-cause mortality risks relative to Normal Weight-II were elevated for underweight (<BMI 18.5; HR = 4.92, p<0.0138), Normal Weight-I (BMI 18.5-22.9; HR = 3.41, p = 0.0149), and Overweight-Obese (BMI>30.0; HR = 4.05,p = 0.0423). Among the old (≥65 years), however, Overweight and Obese categories were not significantly associated with increased all-cause mortality (HR from 0.98 to 1.29), but Overweight-Obese was associated with increased CVD and stroke mortality (HR = 10.0, p = 0.0086).

CONCLUSION

BMI showed a U-shaped relationship with mortality. Among older persons aged 65 and above, the overweight-or-obese category of BMI was not associated with excess all-cause mortality.

Global Metabolic Profiling of Plasma Shows that Three-Year Mild-Caloric Restriction Lessens an Age-Related Increase in Sphingomyelin and Reduces L-leucine and L-phenylalanine in Overweight and Obese Subjects

The effect of weight loss from long-term, mild-calorie diets (MCD) on plasma metabolites is unknown. This study was to examine whether MCD-induced weight reduction caused changes in the extended plasma metabolites. Overweight and obese subjects aged 40-59 years consumed a MCD (approximately 100 kcal/day deficit, n=47) or a weight-maintenance diet (control, n=47) in a randomized, controlled design with a three-year clinical intervention period and plasma samples were analyzed by using UPLC-LTQ-Orbitrap mass spectrometry. The three-year MCD intervention resulted in weight loss (-8.87%) and significant decreases in HOMA-IR and TG. The three-year follow-up of the MCD group showed reductions in the following 13 metabolites: L-leucine; L-phenylalanine; 9 lysoPCs; PC (18:0/20:4); and SM (d18:0/16:1). The three-year MCD group follow-up identified increases in palmitic amide, oleamide, and PC (18:2/18:2). Considering the age-related alterations in the identified metabolites, the MCD group showed a greater decrease in L-leucine, L-phenylalanine, and SM (d18:0/16:1) compared with those of the control group. Overall, the change (Δ) in BMI positively correlated with the ΔTG, ΔHOMA-IR, ΔL-leucine, and ΔSM (d18:0/16:1). The ΔHOMA-IR positively correlated with ΔTG, ΔL-leucine, ΔL-phenylalanine, and ΔSM (d18:0/16:1). The weight loss resulting from three-year mild-caloric restriction lessens the age-related increase in SM and reduces L-leucine and L-phenylalanine in overweight and obese subjects. These changes were coupled with improved insulin resistance (ClinicalTrials.gov: NCT02081898).

Alcohol consumption and mortality in patients undergoing coronary artery bypass graft (CABG)-a register-based cohort study

BACKGROUND

Previous studies have shown that compared with abstinence and heavy drinking, moderate alcohol consumption is associated with a reduced risk of mortality among the general population and patients with heart failure and myocardial infarction. We examined the association between alcohol consumption and mortality in coronary artery bypass graft (CABG) patients.

METHOD

We studied 1,919 first-time CABG patients using data on alcohol consumption and mortality obtained from Danish national registers from March 2006 to October 2011. Alcohol consumption was divided into the following groups: abstainers (0 units/week), moderate consumers (1-14 units/week), moderate-heavy drinkers (15-21 units/week) and heavy drinkers (>21 units/week). Hazard ratios (HR) of all-cause mortality were calculated using Cox proportional hazard regression analysis.

RESULTS

The median follow-up was 2.2 years [IQR 2.0]. There were 112 deaths, of which 96 (86 %) were classified as cardiovascular. Adjustments for age and sex showed no increased risk of all-cause mortality for the abstainers (HR 1.61, 95 % CI, 1.00-2.58) and moderate-heavy drinkers (HR 1.40, 95 % CI, 0.73-2.67) compared with moderate consumers. However, heavy drinkers had a high risk of all-cause mortality compared with moderate consumers (HR 2.44, 95 % CI, 1.47-4.04). A full adjustment showed no increase in mortality for the abstainers (HR 1.59, 95 % CI, 0.98-2.57) and moderate-heavy drinkers (HR 1.68, 95 % CI, 0.86-3.29), while heavy drinkers were associated with an increased mortality rate (HR 1.88, 95 % CI, 1.10-3.21). There was no increased risk of 30-day mortality for the abstainers (HR 0.74, 95 % CI, 0.23-2.32), moderate-heavy drinkers (HR 0.36, 95 % CI, 0.07-1.93) and heavy drinkers (HR 2.20, 95 % CI, 0.65-7.36).

CONCLUSION

There was no increased risk of mortality for abstainers (0 units/week) or moderate-heavy drinkers (15-21 units/week) following a CABG. Only heavy drinking (>21 units/week) were significantly associated with an increased mortality rate. These results suggest that only heavy drinking present a risk factor among CABG patients.

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.

Differences in the distribution of risk factors for stroke among the high-risk population in urban and rural areas of Eastern China

INTRODUCTION

Considering the program of screening for risk factors of stroke in Eastern China, the aim of this study was to compare the distribution differences in risk factors for stroke among the high-risk population living in urban and rural areas.

METHODS

A total of 231,289 residents were screened and basic information collected. Risk factors for stroke among the high-risk population were compared between the urban and rural groups.

RESULTS

A total of 117,776 high-risk residents from urban areas and 113,513 from rural areas were included in the analysis. The prevalence of hypertension was much higher in rural areas (73.3%) than that in urban areas (64.1%). Dyslipidemia (48.9% vs. 26.9%), sport lack (46.6% vs. 31.6%), diabetes mellitus (21.3% vs. 16.5%), and atrial fibrillation (18.7% vs. 9.8%) were more prevalent in the urban group, while smoking (26.5% vs. 28.8%), previous stroke (10.1% vs. 16.9%), and transient ischemic attack (20.9% vs. 24.6%) were less prevalent.

CONCLUSION

Among the population at high risk of stroke, there were significant differences in the distribution of the following risk factors between the urban and rural groups: hypertension, atrial fibrillation, dyslipidemia, lack of physical exercise, and a previous stroke.

The Harbin Cohort Study on Diet, Nutrition and Chronic Non-communicable Diseases: study design and baseline characteristics

Diet and nutrition have been reported to be associated with many common chronic diseases and blood-based assessment would be vital to investigate the association and mechanism, however, blood-based prospective studies are limited. The Harbin Cohort Study on Diet, Nutrition and Chronic Non-communicable Diseases was set up in 2010. From 2010 to 2012, 9,734 participants completed the baseline survey, including demographic characteristics, dietary intake, lifestyles and physical condition, and anthropometrics. A re-survey on 490 randomly selected participants was done by using the same methods which were employed in the baseline survey. For all participants, the mean age was 50 years and 36% of them were men. Approximately 99.4 % of cohort members donated blood samples. The mean total energy intake was 2671.7 kcal/day in men and 2245.9 kcal/day in women, the mean body mass index was 25.7 kg/m² in men and 24.6 kg/m² in women, with 18.4% being obese (≥28 kg/m²), 12.7% being diabetic, and 29.5% being hypertensive. A good agreement was obtained for the physical measurements between the baseline survey and re-survey. The resources from the cohort and its fasting and postprandial blood samples collected both at baseline and in each follow-up will be valuable and powerful in investigating relationship between diet, nutrition and chronic diseases and discovering novel blood biomarkers and the metabolism of these biomarkers related to chronic diseases.

Changes in BMI before and during economic development and subsequent risk of cardiovascular disease and total mortality: a 35-year follow-up study in China

OBJECTIVE

It is unclear whether changes in BMI during rapid economic development influence subsequent mortality.

RESEARCH DESIGN AND METHODS

We analyzed whether BMI in 1976 and 1994 and changes in BMI during 1976-1994 predict cardiovascular disease (CVD) and all-cause mortality in a 35-year follow-up cohort of 1,696 Chinese (1,124 men and 572 women, aged 35-65 years) in Xi'an, China. Participants were categorized as underweight (<18.5 kg/m(2)), normal weight (18.5-24.9 kg/m(2)), and overweight (≥25.0 kg/m(2)).

RESULTS

During 51,611 person-years of follow-up, we identified 655 deaths from all causes and 234 from CVD. From 1976 to 1994, the prevalence of overweight rose from 9.2 to 27.8%. With each unit increment in 1976 BMI, multivariate hazard ratios (HRs) (95% CI) were 0.78 (0.72-0.84) for CVD and 0.91 (0.87-0.95) for all-cause mortality. In contrast, corresponding HRs were 1.14 (1.08-1.19) and 1.05 (1.01-1.08) in 1994 BMI. The HRs for each unit increment in BMI change from 1976 to 1994 were 1.35 (1.25-1.41) for CVD and 1.09 (1.05-1.13) for all-cause mortality. Compared with participants with stable normal weight in 1976 and 1994, HRs of all-cause mortality for those who had normal weight in 1976 but became overweight in 1994 and for those who were persistently overweight during 1976-1994 were 1.42 (1.12-1.80) and 1.80 (1.04-3.14), respectively.

CONCLUSIONS

Gaining weight with increased BMI at middle age in Chinese during economic development was associated with elevated risks of all-cause and CVD mortality. Higher BMI measured before economic development was associated with lower mortality risk, whereas BMI measured afterward was associated with increased mortality.

Risk factors of stroke in Western and Asian countries: a systematic review and meta-analysis of prospective cohort studies

Background

There has been an increasing trend in the incidence of stroke worldwide in recent years, and the number of studies focusing on the risk factors for stroke has also increased every year. To comprehensively evaluate the risk factors of stroke identified in prospective Western and Asian cohort studies.

Methods

Population-based cohort studies on stroke were searched in databases (PubMed, EMBASE, Web of Science, Google Scholar, etc.), and the library of the Third Military Medical University was manually searched for relevant information. A meta-analysis of Western and Asian studies on risk factors was performed. The pooled hazard ratios (HRs) with 95% confidence intervals (CIs) were calculated to assess the final group of cohort studies.

Results

After screening, 22 prospective cohort studies were included in the analyses of this investigation. Two factors, smoking and alcohol consumption, showed statistically significant differences between Western and Asian populations, and the results were as follows (W/A): 2.05 (95% CI, 1.68 ~ 2.49)/1.27 (95% CI, 1.04 ~ 1.55) and 0.89 (95% CI, 0.76 ~ 1.04)/1.28 (95% CI, 1.07 ~ 1.53). The factor BMI = 18.5-21.9 kg/m² showed statistically significant differences only in Western populations, 0.96 (95% CI, 0.93 ~ 0.99); the factor SBP = 120-139 mm Hg showed statistically significant differences only in Asian populations, 2.29 (95% CI, 1.04 ~ 5.09).

Conclusions

The prevalences of risk factors affect the stroke morbidity in Western and Asian populations, which may be biased by race. The meta-analysis of population-based studies suggests that different preventive measures should be adopted for Western and Asian population groups that are at high risk for stroke.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2458-14-776) contains supplementary material, which is available to authorized users.

Association between body mass index and cause-specific mortality as well as hospitalization in frail Chinese older adults

AIM

A U-shaped relationship between body mass index (BMI) and all-cause mortality has been reported, but there are few studies examining the association between BMI and cause-specific mortality and hospitalization. We carried out a longitudinal study to examine these associations in Chinese older adults with multiple comorbidities, which could provide a reference for the recommended BMI in this population.

METHODS

From 2004 to 2013, a retrospective cohort of Chinese older adults was selected from a geriatric day hospital in Hong Kong. They were divided into groups according to their BMI: BMI <16; BMI 16-18; BMI 18.1-20; BMI 20.1-22; BMI 22.1-24; BMI 24.1-26; BMI 26.1-28; BMI 28.1-30 and BMI >30. Other assessments included medical, functional, cognitive, social and nutritional assessment.

RESULTS

A total of 1747 older adults (mean age 80.8 ± 7.1 years, 44.1% male, 46.1% living in nursing homes, Charlson Comorbidity Index 2.0 ± 1.6) with a median follow up of 3.5 years were included. Older adults with BMI 24-28 had the lowest all-cause, infection-related and cardiovascular mortality (P < 0.001). Multivariate analysis showed that there was an inverted J-shaped association between BMI and hazard ratio for all-cause and infection-related mortality in both nursing home and community-dwelling older adults. The rate of all-cause hospitalization was lower in older adults with BMI 22-28 (P = 0.002). Multivariate analysis showed that there was an inverted J-shaped association between the odds ratio of recurrent hospitalization and BMI.

CONCLUSION

Chinese older adults with BMI 24-28 had lower all-cause mortality, infection-related mortality, cardiovascular-related mortality and all-cause hospitalization. This study provides a reference for the recommended BMI in this population.

Association between body mass index and cardiovascular disease mortality in east Asians and south Asians: pooled analysis of prospective data from the Asia Cohort Consortium

OBJECTIVE

To evaluate the association between body mass index and mortality from overall cardiovascular disease and specific subtypes of cardiovascular disease in east and south Asians.

DESIGN

Pooled analyses of 20 prospective cohorts in Asia, including data from 835,082 east Asians and 289,815 south Asians. Cohorts were identified through a systematic search of the literature in early 2008, followed by a survey that was sent to each cohort to assess data availability.

SETTING

General populations in east Asia (China, Taiwan, Singapore, Japan, and Korea) and south Asia (India and Bangladesh).

PARTICIPANTS

1,124,897 men and women (mean age 53.4 years at baseline).

MAIN OUTCOME MEASURES

Risk of death from overall cardiovascular disease, coronary heart disease, stroke, and (in east Asians only) stroke subtypes.

RESULTS

49,184 cardiovascular deaths (40,791 in east Asians and 8393 in south Asians) were identified during a mean follow-up of 9.7 years. East Asians with a body mass index of 25 or above had a raised risk of death from overall cardiovascular disease, compared with the reference range of body mass index (values 22.5-24.9; hazard ratio 1.09 (95% confidence interval 1.03 to 1.15), 1.27 (1.20 to 1.35), 1.59 (1.43 to 1.76), 1.74 (1.47 to 2.06), and 1.97 (1.44 to 2.71) for body mass index ranges 25.0-27.4, 27.5-29.9, 30.0-32.4, 32.5-34.9, and 35.0-50.0, respectively). This association was similar for risk of death from coronary heart disease and ischaemic stroke; for haemorrhagic stroke, the risk of death was higher at body mass index values of 27.5 and above. Elevated risk of death from cardiovascular disease was also observed at lower categories of body mass index (hazard ratio 1.19 (95% confidence interval 1.02 to 1.39) and 2.16 (1.37 to 3.40) for body mass index ranges 15.0-17.4 and <15.0, respectively), compared with the reference range. In south Asians, the association between body mass index and mortality from cardiovascular disease was less pronounced than that in east Asians. South Asians had an increased risk of death observed for coronary heart disease only in individuals with a body mass index greater than 35 (hazard ratio 1.90, 95% confidence interval 1.15 to 3.12).

CONCLUSIONS

Body mass index shows a U shaped association with death from overall cardiovascular disease among east Asians: increased risk of death from cardiovascular disease is observed at lower and higher ranges of body mass index. A high body mass index is a risk factor for mortality from overall cardiovascular disease and for specific diseases, including coronary heart disease, ischaemic stroke, and haemorrhagic stroke in east Asians. Higher body mass index is a weak risk factor for mortality from cardiovascular disease in south Asians.

Ideal cardiovascular health metrics on the prevalence of asymptomatic intracranial artery stenosis: a cross-sectional study

Background and Purpose

Intracranial Artery Stenosis (ICAS) is one of the most common causes of ischemic stroke in Asia. Previous studies have shown the number of ideal cardiovascular health (CVH) metrics was associated with lower risk of stroke. This study aimed to investigate the relationship between ideal CVH metrics and prevalence of ICAS.

Methods

A random sample of 5,412 participants (selected from Kailuan Study as a reference population) aged 40 years or older (40.10% women), free of stroke, transient ischemic attack, and coronary disease, were enrolled in the Asymptomatic Polyvascular Abnormalities Community study from 2010 to 2011. We collected information on the seven CVH metrics (including smoking, body mass index, dietary intake, physical activity, blood pressure, total cholesterol and fasting blood glucose); and assessed ICAS by transcranial Doppler. The relationship between the ideal CVH metrics and prevalence of ICAS was analyzed using the multivariate logistic regression.

Results

After adjusting for age, sex, and other potential confounders, the adjusted odds ratios(95% confidence interval) for ICAS were 0.76(0.58–0.99), 0.55(0.43–0.72), 0.49(0.37–0.65), 0.43(0.31–0.61), and 0.36(0.22–0.62), respectively, for those having 2, 3, 4, 5, and 6–7 ideal CVH metrics compared with those having 0–1 ideal metric(p-trend<0.0001). Similar inverse associations were observed in different age and gender groups (all p-trends<0.05).

Conclusion

We found a clear gradient relationship between the number of ideal CVH metrics and lower prevalence of ICAS in a Chinese population, which supports the importance of ideal health behaviors and factors in the prevention of ICAS.

Serial study on the association between body mass index and hypertension in rural Japanese

The objective of this study was to examine the association between body mass index (BMI) and blood pressure. Two sets of cross-sectional data were obtained from annual health examinations for adults aged 40 years and over (n=1,327 in 1993; n=1,302 in 2000) in Tsunagi area of Kumamoto Prefecture, Japan. BMI was associated with mean blood pressure and with prevalence of hypertension both in 1993 and 2000. The association was independent of age, smoking status and alcohol consumption. A significant increase in risk of hypertension was found in most categories of BMI 25.0 and above, and a greater than three fold increase in those with BMI of 27 and above compared with those with BMI of 18.5-22.9. Although mean blood pressure and prevalence of hypertension sharply decreased in 2000 compared with that in 1993, BMI was positively and independently associated with increased blood pressure.

Body Fat and Fat-Free Mass and All-Cause Mortality

OBJECTIVE

To investigate whether the association between BMI and all-cause mortality could be disentangled into opposite effects of body fat and fat-free mass (FFM).

RESEARCH METHODS AND PROCEDURES

All-cause mortality was studied in the Danish follow-up study "Diet, Cancer and Health" with 27,178 men and 29,875 women 50 to 64 years old recruited from 1993 to 1997. By the end of year 2001, the median follow-up was 5.8 years, and 1851 had died. Body composition was assessed by bioelectrical impedance. Cox regression models were used to estimate the relationships among body fat mass index (body fat mass divided by height squared), FFM index (FFM divided by height squared), and mortality. All analyses were adjusted for smoking habits.

RESULTS

Men and women showed similar associations. J-shaped associations were found between body fat mass index and mortality adjusted for FFM and smoking. The mortality rate ratios in the upper part of body fat mass were 1.12 per kg/m2 (95% confidence interval: 1.07, 1.18) in men and 1.06 per kg/m2 (95% confidence interval: 1.02, 1.10) in women. Reversed J-shaped associations were found between FFM index and mortality with a tendency to level off for high values of FFM.

DISCUSSION

Our findings suggest that BMI represents joint but opposite associations of body fat and FFM with mortality. Both high body fat and low FFM are independent predictors of all-cause mortality.

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

BACKGROUND

In China, there have been few large prospective studies of the associations of body mass index (BMI) with overall and cause-specific mortality that have simultaneously controlled for biases that can be caused by pre-existing disease and smoking.

METHODS

Prospective cohort study of 224 064 men, of whom 40 700 died during follow-up between 1990-91 and 2006. Analyses restricted to 142 214 men aged 40-79 years at baseline with no disease history and, to further reduce bias from pre-existing disease, at least 5 years of subsequent follow-up, leaving 17 800 deaths [including 4165 stroke, 1297 coronary heart disease (CHD), 3121 chronic obstructive pulmonary disease (COPD)]. Adjusted hazard ratios (HRs) and 95% confidence intervals (95% CIs) per 5 kg/m(2) calculated within either a lower (15 to <23.5 kg/m(2)) or higher (23.5 to <35 kg/m(2)) range.

RESULTS

The association between BMI and all-cause mortality was U-shaped with the lowest mortality at ∼22.5-25 kg/m(2). In the lower range, 5 kg/m(2) higher BMI was associated with 14% lower mortality (HR 0.86, 95% CI 0.82-0.91); in the upper range, it was associated with 27% higher mortality (HR 1.27, 95% CI 1.15-1.40). The absolute excess mortality in the lower range was largely accounted for by excess mortality from specific smoking-related diseases: 54% by that for COPD, 12% other respiratory disease, 13% lung cancer, 11% stomach cancer. The excess mortality in the upper BMI range was largely accounted for by excess mortality from specific vascular diseases: 55% by that for stroke, 16% CHD. In this range, 5 kg/m(2) higher BMI was associated with ∼50% higher mortality from stroke (HR 1.61, 95% CI 1.36-1.92) and CHD (HR 1.48, 95% CI 1.12-1.95).

CONCLUSIONS

For China, previous evidence may have overestimated the excess mortality at low BMI but underestimated that at high BMI. The main way obesity kills in China appears to be stroke.

China Kadoorie Biobank of 0.5 million people: survey methods, baseline characteristics and long-term follow-up

BACKGROUND

Large blood-based prospective studies can provide reliable assessment of the complex interplay of lifestyle, environmental and genetic factors as determinants of chronic disease.

METHODS

The baseline survey of the China Kadoorie Biobank took place during 2004-08 in 10 geographically defined regions, with collection of questionnaire data, physical measurements and blood samples. Subsequently, a re-survey of 25,000 randomly selected participants was done (80% responded) using the same methods as in the baseline. All participants are being followed for cause-specific mortality and morbidity, and for any hospital admission through linkages with registries and health insurance (HI) databases.

RESULTS

Overall, 512,891 adults aged 30-79 years were recruited, including 41% men, 56% from rural areas and mean age was 52 years. The prevalence of ever-regular smoking was 74% in men and 3% in women. The mean blood pressure was 132/79 mmHg in men and 130/77 mmHg in women. The mean body mass index (BMI) was 23.4 kg/m(2) in men and 23.8 kg/m(2) in women, with only 4% being obese (>30 kg/m(2)), and 3.2% being diabetic. Blood collection was successful in 99.98% and the mean delay from sample collection to processing was 10.6 h. For each of the main baseline variables, there is good reproducibility but large heterogeneity by age, sex and study area. By 1 January 2011, over 10,000 deaths had been recorded, with 91% of surviving participants already linked to HI databases.

CONCLUSION

This established large biobank will be a rich and powerful resource for investigating genetic and non-genetic causes of many common chronic diseases in the Chinese population.

Body mass index and all-cause mortality in a large Chinese cohort

BACKGROUND

Obesity is known to be associated with an increased risk of death, but current definitions of obesity are based on data from white populations. We examined the association between body mass index (BMI) and the risk of death in a large population of adult Chinese people.

METHODS

We examined the association between body mass index (BMI) and all-cause mortality prospectively among 58,738 men and 65,718 women aged 20 years and older enrolled in 1998-1999 from four national health screening centres in Taiwan. We used Cox proportional hazards regression analyses to estimate the relative risks of all-cause mortality for different BMI categories during a maximum follow-up of 10 years.

RESULTS

A total of 3947 participants died during the follow-up period. The lowest risk of death was observed among men and women who had a BMI of 24.0-25.9 (mean 24.9). After adjustment for age, smoking status, alcohol intake, betel-nut chewing, level of physical activity, income level and education level, we observed a U-shaped association between BMI and all-cause mortality. Similar U-shaped associations were observed when we analyzed data by age (20-64 or ≥ 65 years), smoking (never, < 10 pack-years or ≥ 10 pack-years) and presence of a pre-existing chronic disease, and after we excluded deaths that occurred in the first three years of follow-up.

INTERPRETATION

BMI and all-cause mortality had a U-shaped association among adult Chinese people in our study. The lowest risk of death was among adults who had a BMI of 24.0-25.9 (mean 24.9). Our findings do not support the use of a lower cutoff value for overweight and obesity in the adult Chinese population.

BMI, all-cause and cause-specific mortality in Chinese Singaporean men and women: the Singapore Chinese health study

Background

The optimal range of relative weight for morbidity and mortality in Asian populations is an important question in need of more thorough investigation, especially as obesity rates increase. We aimed to examine the association between body mass index (BMI), all cause and cause-specific mortality to determine the optimal range of BMI in relation to mortality in Chinese men and women in Singapore.

Methodology/Principal Findings

We analyzed data from a prospective cohort study of 51,251 middle-aged or older (45–74) Chinese men and women in the Singapore Chinese Health Study. Participants were enrolled and data on body weight and covariates were collected in 1993–1998 and participants were followed through 2008. The analysis accounted for potential methodological issues through stratification on smoking and age, thorough adjustment of demographic and lifestyle confounders and exclusion of deaths early in the follow-up.

Conclusions/Significance

Increased risk of mortality was apparent in underweight (<18.5) and obese BMI categories (≥27.5) independent of age and smoking. Regardless of age or BMI, smoking considerably increased the rate of mortality and modified the association between BMI and mortality. The most favorable range of BMI for mortality rates and risk in non-smoking persons below age 65 was 18.5–21.4 kg/m², and for non-smoking persons aged 65 and above was 21.5–24.4 kg/m².

Effects of physical activity, body mass index, waist-to-hip ratio and waist circumference on total mortality risk in the Swedish National March Cohort

The health benefits of physical activity (PA) have been well documented. However, there is less research investigating whether or not these health benefits might differ among males and females or among subjects characterized by different levels of body mass index (BMI), waist-to-hip ratio (WHR), and waist circumference (WC). Baseline total PA, BMI, WHR and waist circumference were measured in 14,585 men and 26,144 women who participated in the Swedish National March. Their effects on all-cause mortality were analyzed with a follow-up time of almost 10 years. Sedentary men with a BMI ≥ 30 had a 98% (95% CI: 30-201%) increased risk of mortality compared to normal weight men with a high level of total PA. The same trend was observed for sedentary men with high WHR or waist circumference, compared to lean and highly active men. Sedentary women with a waist circumference of 88 cm or more had almost doubled, i.e. 97% (95% CI: 35-189%) increased mortality risk compared to physically active women with a waist circumference below 80 cm. BMI in men, but waist circumference in women better forecast all-cause mortality. We found no substantial effect modification between different measures of adiposity and physical activity-physical inactivity and obesity seem to increase total mortality risk independently and additively.

Soybean isoflavone exposure does not have feminizing effects on men: a critical examination of the clinical evidence

OBJECTIVE

To critically evaluate the clinical evidence, and when not available, the animal data, most relevant to concerns that isoflavone exposure in the form of supplements or soy foods has feminizing effects on men.

DESIGN

Medline literature review and cross-reference of published data.

RESULT(S)

In contrast to the results of some rodent studies, findings from a recently published metaanalysis and subsequently published studies show that neither isoflavone supplements nor isoflavone-rich soy affect total or free testosterone (T) levels. Similarly, there is essentially no evidence from the nine identified clinical studies that isoflavone exposure affects circulating estrogen levels in men. Clinical evidence also indicates that isoflavones have no effect on sperm or semen parameters, although only three intervention studies were identified and none were longer than 3 months in duration. Finally, findings from animal studies suggesting that isoflavones increase the risk of erectile dysfunction are not applicable to men, because of differences in isoflavone metabolism between rodents and humans and the excessively high amount of isoflavones to which the animals were exposed.

CONCLUSION(S)

The intervention data indicate that isoflavones do not exert feminizing effects on men at intake levels equal to and even considerably higher than are typical for Asian males.

Urinary total isothiocyanates and colorectal cancer: a prospective study of men in Shanghai, China

Laboratory and epidemiologic evidence suggests that dietary isothiocyanates (ITCs) may have a chemopreventive effect on cancer. Humans are exposed to ITCs primarily through ingestion of cruciferous vegetables that contain glucosinolates, the precursors to ITCs. The association between urinary total ITC level and colorectal cancer risk was examined in a cohort of 18,244 men in Shanghai, China, with 16 years of follow-up. Urinary total ITCs were quantified on 225 incident cases of colorectal cancer and 1,119 matched controls. Odds ratios (ORs) and their 95% confidence intervals (95% CIs) were calculated using logistic regression models. High levels of urinary total ITCs were associated with a reduced risk of colorectal cancer 5 years after baseline measurements of ITCs, whereas a statistically nonsignificant increase in the risk of colorectal cancer was observed for cases within 5 years of post-enrollment (OR, 1.93; 95% CI, 0.85-4.39 for the upper three quartiles of urinary ITCs versus the lowest quartile). The inverse ITC-colorectal cancer association became stronger with a longer duration of follow-up. Compared with the first quartile, ORs (95% CIs) for the second, third, and fourth quartiles of total ITCs in urine collected 10 or more years before cancer diagnosis were 0.61 (0.35-1.05), 0.51 (0.29-0.92), and 0.46 (0.25-0.83), respectively, for risk of colorectal cancer (P for trend = 0.006). The present study suggests that dietary ITCs may exert tumor inhibitory effects, especially during earlier stages of the multistage process of carcinogenesis.

Are Asians at greater mortality risks for being overweight than Caucasians? Redefining obesity for Asians

OBJECTIVES

To assess whether overweight Asians, assessed on the basis of WHO criteria, are at greater mortality risk than overweight Caucasians, and to determine whether alternative cut-off points (BMI = 23.0-24.9 kg/m2 for overweight and BMI >or= 25.0 kg/m2 for obesity) suggested by the WHO Western Pacific Regional Office are appropriate.

DESIGN

The cohort was followed prospectively until the end of 2001. All-cause and CVD mortality risks of the overweight and obese group, relative to the reference group (BMI = 18.5-24.9 or 18.5-22.9 kg/m2), were assessed using Cox regression analysis, adjusting for age, smoking and gender. Excess deaths were estimated with a method proposed by the US Centers for Disease Control and Prevention.

SETTING

National Health Interview Survey (NHIS 2001) and a middle-aged perspective cohort in Taiwan.

SUBJECTS

Subjects comprised 36 386 civil servants and school teachers, aged 40 years and older, who underwent a medical examination during 1989-1992.

RESULTS

In the WHO-defined overweight group, Asians showed a significant increase in all-cause mortality risk compared with Caucasians. Asians showed risks equivalent to Caucasians' at lower BMI (around 5 units). Every unit of BMI increase, at 25.0 kg/m2 or above, was associated with a 9 % increase in relative mortality risk from all causes. Applying a cut-off point of 25.0 kg/m2 for obesity would result a prevalence of 27.1 %, while the traditional WHO cut-off point of 30.0 kg/m2 yielded obesity prevalence of 4.1 %. Excess deaths due to obesity accounted for 8.6 % of all deaths and 21.1 % of CVD deaths, based on the alternative cut-offs.

CONCLUSIONS

In this Asian population, significant mortality risks started at BMI >or= 25.0 kg/m2, rather than at BMI >or= 30.0 kg/m2. The study supports the use of BMI >or= 25.0 kg/m2 as a new cut-off point for obesity and BMI = 23.0-24.9 kg/m2 for overweight. The magnitude of obesity-attributable deaths has been hitherto under-appreciated among Asians.

Body mass index, weight change and mortality risk in a prospective study in India

BACKGROUND

Although the detrimental effect of overweight and obesity has been extensively reported in Western populations, little is known on the association between body weight, weight change and mortality in Asian populations whose weight distribution and mortality differ considerably from the West.

METHODS

A cohort of 75 868 subjects aged 35 years and above, participants of the Trivandrum Oral Cancer Study-a cluster-randomized controlled trial originally implemented to evaluate the efficacy of visual inspection on oral cancer, in Kerala State, South India-were followed up from 1995 to 2004. Weight and height were measured both at baseline and in 3.5-year follow-up surveys. Early years of follow-up were excluded from the analyses. Relative risks of overall death and cause-specific death were estimated according to the body mass index (BMI) category of the WHO Asian population definitions, and to weight changes between two surveys.

RESULTS

Low BMI was a predictor of mortality, while high BMI was not. Mortality risks in men adjusted for age, smoking habits and other potential confounders, as compared with a BMI 18.5-22.9 kg/m(2), were 1.26 (95% CI 1.03-1.55) for BMI < 16 kg/m(2); 1.16 (1.03-1.32) for BMI = 16-18.4 kg/m(2); 0.95 (0.81-1.12) for BMI = 23-24.9 kg/m(2); 0.85 (0.69-1.05) for BMI = 25-27.4 kg/m(2); and 0.89 (0.65-1.21) for BMI >/= 27.5 kg/m(2). Similar findings were observed in women. BMI was not associated with deaths from cancer, cardiovascular and cerebrovascular diseases, and diabetes. A low BMI (<16 kg/m(2)) was associated with increased deaths from chronic respiratory diseases. Smoking and socio-economical status did modify the association. A moderate weight gain of 4-10% between the two surveys was associated with decreased risk of death, while moderate and severe weight loss were predictive factors of death. Similar results were observed in both men and women.

CONCLUSIONS

Among this Indian rural population, mild to severe leanness (BMI < 16 kg/m(2)) and weight loss were important determinants of mortality, especially from chronic respiratory diseases, while overweight and above (BMI > 23 kg/m(2)) did not show any detrimental effect.

Body mass index and mortality in patients with acute venous thromboembolism: findings from the RIETE registry

BACKGROUND

There is little information on the influence of body mass index (BMI) on mortality in patients with acute venous thromboembolism (VTE).

PATIENTS AND METHODS

RIETE is an ongoing registry of consecutive patients with symptomatic, objectively confirmed, acute VTE. We examined the association between BMI and mortality during the first 3 months of therapy.

RESULTS

Of the 10 114 patients enrolled as of March 2007: 153 (1.5%) were underweight (BMI < 18.5); 2882 (28%) had a normal weight (BMI 18.5-24.9); 4327 (43%) were overweight (BMI 25.0-30); and 2752 (27%) were obese (BMI > 30). The overweight and obese patients were significantly older, and were less likely to have had cancer, recent immobility or renal insufficiency. After 3 months of therapy their death rates were 28%, 12%, 6.2% and 4.2%, respectively. In multivariate analysis, the relative risks for death after adjusting for confounding variables including age, cancer, renal insufficiency or idiopathic VTE were: 2.1 (95% CI, 1.5-2.7); 1.0 (reference); 0.6 (95% CI, 0.5-0.7); and 0.5 (95% CI, 0.4-0.6), respectively. The rates of fatal pulmonary embolism (2.0%, 2.1%, 1.2% and 0.8%, respectively) also decreased with BMI. There were no differences in the rate of fatal bleeding, but patients who were underweight had an increased incidence of major bleeding complications (7.2% vs. 2.7%; odds ratio, 2.7; 95% CI, 1.4-5.1).

CONCLUSIONS

Obese patients with acute VTE have less than half the mortality rate when compared with normal BMI patients. This reduction in mortality rates was consistent among all subgroups and persisted after multivariate adjustment.

Plasma lipoprotein (a), homocysteine, and other cardiovascular disease (CVD) risk factors in Nigerians with CVD

Elevated plasma lipoprotein (a) (Lp(a)) and total homocysteine (tHcy) concentrations, as well as fat distributions, are associated with cardiovascular disease (CVD) risk. The purpose of this study was to evaluate plasma Lp(a), tHcy, percentage body fat, anthropometric indices, and blood pressure (BP) and their relationships with each other in well-defined, hospital-based, CVD patients in a Nigerian African community. One hundred seventy patients suffering from hypertensive heart disease, hypertension, ischaemic heart disease, and myocardial infraction with the mean age of 45.3 ± 1.3 years and 58 apparently healthy volunteers with the mean age of 44.8 ±1.2 years were selected. Anthropometric indices and BP were measured. Percentage body fat, body mass index, and waist-to-hip ratio (WHR) were calculated. Plasma Lp(a) and tHcy concentrations were determined. The results showed significant increases in BP, skinfold thickness (SFT) variables, and WHR in all of the CVD patients. Plasma Lp(a) was also significantly increased (p < 0.001), whereas the slight increase in the mean tHcy was not statistically significant. Positive significant correlations were found between systolic BP, triceps, SFT, and percentage body fat (p < 0.01), whereas significant correlations were found between some body composition variables, tHcy, and systolic BP (p < 0.05). Our findings provide supportive evidence for altered plasma Lp(a) concentration in addition to some other traditional CVD risk factors in Nigerians. The role of homocysteine is not well defined.

Risk factors in V-shaped risk associations with all-cause mortality in type 2 diabetes-The Hong Kong Diabetes Registry

BACKGROUND

Body mass index (BMI) is associated with death in a V-shaped manner in general populations but it is unknown whether BMI or other risk factors also exhibit V-shaped relationships with death in type 2 diabetic patients.

METHODS

A prospective cohort of 7534 Chinese, type 2 diabetic patients enrolled since 1995 were censored on 30 July 2005. Spline Cox regression analysis with a stepwise algorithm (p < 0.05) was used to select predictors. Hazard ratio (HR) curves were used to explore the relationships, which were confirmed by standard Cox models.

RESULTS

763 patients died during the 5.5 years of follow-up. BMI, high-density lipoprotein cholesterol (HDL-C) and white blood cell (WBC) count were related to all-cause mortality in a V-shaped manner. The nadirs of the risk curves were at 26 kg/m(2) for BMI, 1.15 mmol/L for HDL-C and 6.25 x 10(9) counts/L for WBC. The multivariate hazard ratio of BMI away from 26.0 kg/m(2) was 1.08; HDL-C, 1.06 per mmol/L for values less than the nadir and 6.97 per mmol/L for greater than the nadir; and WBC, 1.16 per 10(9) count/L for less than 6.25 x 10(9) and 1.47 for greater than the nadir. Respiratory and neoplastic deaths were the major contributors to the increased death in patients with low or high BMI. Neoplastic death was the major contributor to the increased death in those with low WBC. Genitourinary death was the major contributor to the increased death in those with low and high HDL-C.

CONCLUSION

BMI, HDL-C and WBC are associated with death in a V-shaped manner in type 2 diabetic patients.

All-cause mortality and risk factors in a cohort of retired military male veterans, Xi'an, China: an 18-year follow up study

BACKGROUND

Risk factors of all-cause mortality have not been reported in Chinese retired military veterans. The objective of the study was to examine the risk factors and proportional mortality in a Chinese retired military male cohort.

METHODS

A total of 1268 retired military men aged 55 or older were examined physically and interviewed using a standard questionnaire in 1987. The cohort was followed up every two years and the study censored date was June30, 2005 with a follow-up of up to 18 years. Death certificates were obtained from hospitals and verified by two senior doctors. Data were entered (double entry) by Foxbase, and analysis was carried out by SAS for Windows 8.2. Multivariate Cox proportional hazard regression model was used to compute hazard ratio (HR) and 95% confidence interval (CI).

RESULTS

The total person-years of follow-up was 18766.28. Of the initial cohort of 1268 men, 491 had died, 748 were alive and 29 were lost to follow up. Adjusted mortality (adjusted for age, blood pressure, body mass index, cholesterol, triglycerides, alcohol, exercise, and existing disease) was 2,616 per 100,000 person years. The proportional mortality of cancer, vascular disease and Chronic Obstructive Pulmonary Disease (COPD) were 39.71%, 28.10% and 16.90% respectively. Multivariate analysis showed that age, cigarettes per day, systolic blood pressure, triglyceride, family history of diseases (hypertension, stroke and cancer), existing diseases (stroke, diabetes and cancer), body mass index, and age of starting smoking were associated with all-cause mortality, HR (95%CI) was1.083(1.062-1.104), 1.026(1.013-1.039), 1.009(1.003-1.015), 1.002(1.001-1.003), 1.330(1.005-1.759), 1.330(1.005-1.759), 1.444(1.103-1.890), 2.237(1.244-4.022), 1.462(1.042-2.051), 2.079(1.051-4.115), 0.963(0.931-0.996)and 0.988(0.978-0.999)respectively. Compared with never-smokers, current smokers had increased risks of total mortality [HR 1.369(1.083-1.731)], CHD [HR 1.805 (1.022-3.188)], and lung cancer [HR 2.939 (1.311-6.585)].

CONCLUSION

The three leading causes of diseases were cancer, CHD and stroke, and COPD. Aging, cigarette smoking, high systolic blood pressure, high triglyceride, family history of cancer, hypertension and stroke, existing cases recovering from stroke, diabetes and cancer, underweight, younger age of smoking were risk factors for all-cause mortality. Quitting cigarette smoking, maintaining normal blood pressure, triglyceride and weight are effect control strategies to prevent premature mortality in this military cohort.

BMI versus the metabolic syndrome in relation to cardiovascular risk in elderly Chinese individuals

OBJECTIVE

The purpose of this study was to evaluate the associations of BMI versus metabolic syndrome with cardiovascular diseases (CVDs) in elderly Chinese individuals.

RESEARCH DESIGN AND METHODS

We conducted a population-based cross-sectional study in an urban sample of 2,334 elderly subjects (943 men and 1,391 women). Subjects were classified by BMI (< or = 18.5, < 24, < 28, and > or = 28 kg/m2) and the presence or absence of metabolic syndrome, which was defined by International Diabetes Federation (IDF) criteria. CVDs included clinically diagnosed coronary heart disease (CHD), stroke, and peripheral arterial disease (PAD).

RESULTS

The prevalence rates of overweight (BMI > or = 25 kg/m2) and metabolic syndrome according to the IDF criteria were 56.3% (53.9% in men and 57.9% in women) and 46.3% (34.8% in men and 54.1% in women), respectively. Increasing BMI was strongly associated with a higher risk of CHD, stroke, and PAD even after adjustments for metabolic syndrome and other CVD risk factors. Stratified analysis of participants with or without metabolic syndrome showed that BMI was independently associated with CHD, stroke, and PAD.

CONCLUSIONS

Both overweight and metabolic syndrome are highly prevalent in this elderly Chinese population. BMI, as a measure of overall adiposity, is strongly associated with increased prevalence of CVD independent of metabolic syndrome.

Body Mass Index and Mortality in Middle-Aged Korean Women

PURPOSE

We sought to evaluate the association between body mass index (BMI) and mortality in Korean women and to determine whether the association differs depending on menopausal status.

METHODS

A total of 338,320 Korean women ages 40 to 64 years categorized into seven groups by BMI level were prospectively followed for mortality from approximately 1994 to 2004.

RESULTS

Multivariable-adjusted analysis using Cox proportional hazards model showed a U-shaped association between BMI and all-cause deaths, with the lowest risk at BMI between approximately 25 and 26.9 kg/m2, even after excluding earlier deaths, which did not change when we did a stratified analysis according to menopausal status. A U-shaped association was observed between BMI and cancer death, and the risk associated with low BMI decreased significantly after excluding earlier cancer deaths. There was a J-shaped association between BMI and coronary heart disease (CHD) with a significantly increased risk at greater BMI (>26 kg/m2). Additional adjustment for possible biological effects of obesity (i.e., serum total cholesterol, glucose, and systolic blood pressure) changed the U-shaped association between BMI and all-causes mortality into an inverse shape and substantially reduced the size of risk for CHD death associated with high BMI level. In stratified analysis, the association between BMI and CHD was positive linear in women at premenopausal status, whereas it was U-shaped in women at postmenopausal status.

CONCLUSIONS

Obesity was associated with an increased risk of mortality in both premenopausal and postmenopausal Korean women, indicating that preventive strategies to control obesity are important even in population with a relatively low mean BMI level.

BMI and morbidity in relation to body composition: a cross-sectional study of a rural community in North-East India

This paper deals with BMI and morbidity in relation to body-fat mass (BFM) and fat-free mass (FFM). The analysis was based on cross-sectional data concerning the age, household income, anthropometry and morbidity of 575 males aged 18–59 years from a rural community in North-East India. Data on morbidity were based on the self-reported morbidity (SRM) of the subjects during the last 4 weeks before the survey, whereas data on BMI and body composition were estimated from anthropometry. It was found that SRM was significantly associated with age and income. However, the relationship between BMI and SRM was not significant after adjusting for age and income. Separating the BMI into body-fat mass index (BFMI being BFM in kg divided by height squared in metres) and fat-free mass index (FFMI being FFM in kg divided by height squared in metres), it was found that BFMI was significantly associated with SRM after adjusting for age, income and FFMI. The subjects with a low (<2·9 kg/m2) BFMI were about 4·7 times (odds ratio 4·7, 95 % CI 2·6, 8·6) more likely to become sick than those with a normal (2·9–5·0 kg/m2) BFMI. In addition, the risk of becoming sick was higher in the subjects with a high (>5·0 kg/m2) BFMI than in those with a normal BFMI (odds ratio 3·9, 95 % CI 1·3, 9·8). However, the relationship between FFMI and morbidity was not clearly perceptible. It is therefore speculated that BMI may not always provide accurate information about the variation in body fat and body composition that is associated with morbidity.

Patterns and Associations of Body Weight Among Older Adults in Two Asian Societies

Body weight has important health implications across the lifespan. Most recent attention has focused on the obesity epidemic that is occurring in many parts of the world. However, underweight is also a concern, particularly in less developed countries. For most health outcomes there is a curvilinear association with body weight, with underweight and overweight (compared to normal weight) being associated with a higher prevalence of chronic debilitating and life-threatening conditions and ultimately mortality. This paper uses data from two nationally-representative surveys of older adults (aged 60 and older) in the Philippines (1996) and Taiwan (1999) to assess the prevalence of underweight and overweight and examine associations between body weight and demographic, socioeconomic, and health characteristics in these populations. Older Filipinos have a modest prevalence of underweight (29.9%) and low prevalence of overweight (12.2%), whereas the reverse is observed in Taiwan (6.4 and 29.3%, respectively). Results show generally expected associations between body weight and demographic characteristics, health conditions and behaviors. We find little evidence of socioeconomic differences in body weight, except in the Philippines where higher SES is associated with a lower risk of being underweight. Implications of the results are discussed in terms of healthy weight maintenance among critical subgroups to potentially reduce the prevalence of disease and improve quality of life.

Body mass index and all-cause mortality in a nationwide US cohort

OBJECTIVE

To investigate whether the nature of the relationship between body mass index (BMI (kg/m2)) and all-cause mortality is direct, J- or U-shaped, and whether this relationship changes as people age.

DESIGN

Prospective nationwide cohort study of US radiologic technologists (USRT).

SUBJECTS

Sixty-four thousand seven hundred and thirty-three female and 19 011 male certified radiation technologists.

METHODS

We prospectively followed participants from the USRT study who completed a mail survey in 1983-1989 through 2000. During an average of 14.7 years of follow-up or 1.23 million person-years, 2278 women and 1495 men died. Using Cox's proportional-hazards regression analyses, we analyzed the relationship between BMI and all-cause mortality by gender and by age group (<55 years; > or = 55 years). We also examined risk in never-smokers after the first 5 years of follow-up to limit bias owing to the confounding effects of smoking and illness-related weight loss on BMI and mortality.

RESULTS

Risks were generally J-shaped for both genders and age groups. When we excluded smokers and the first 5 year of follow-up, risks were substantially reduced in those with low BMIs. In never-smoking women under the age of 55 years (excluding the initial 5-year follow-up period), risk rose as BMI increased above 21.0 kg/m2, whereas in older women, risk increased beginning at a higher BMI (> or = 25.0 kg/m2). Among younger men who never smoked (excluding the initial 5-year follow-up period), risk began to rise above a BMI of 23.0 kg/m2, whereas in older men, risk did not begin to increase until exceeding a BMI of 30.0 kg/m2.

CONCLUSIONS

In younger/middle-aged, but not older, women and men, mortality risks appear directly related to BMI. The more complicated relationship between BMI and mortality in older subjects suggests the importance of assessing whether other markers of body composition better explain mortality risk in older adults.

Overweight, obesity, and mortality in a large prospective cohort of persons 50 to 71 years old

BACKGROUND

Obesity, defined by a body-mass index (BMI) (the weight in kilograms divided by the square of the height in meters) of 30.0 or more, is associated with an increased risk of death, but the relation between overweight (a BMI of 25.0 to 29.9) and the risk of death has been questioned.

METHODS

We prospectively examined BMI in relation to the risk of death from any cause in 527,265 U.S. men and women in the National Institutes of Health-AARP cohort who were 50 to 71 years old at enrollment in 1995-1996. BMI was calculated from self-reported weight and height. Relative risks and 95 percent confidence intervals were adjusted for age, race or ethnic group, level of education, smoking status, physical activity, and alcohol intake. We also conducted alternative analyses to address potential biases related to preexisting chronic disease and smoking status.

RESULTS

During a maximum follow-up of 10 years through 2005, 61,317 participants (42,173 men and 19,144 women) died. Initial analyses showed an increased risk of death for the highest and lowest categories of BMI among both men and women, in all racial or ethnic groups, and at all ages. When the analysis was restricted to healthy people who had never smoked, the risk of death was associated with both overweight and obesity among men and women. In analyses of BMI during midlife (age of 50 years) among those who had never smoked, the associations became stronger, with the risk of death increasing by 20 to 40 percent among overweight persons and by two to at least three times among obese persons; the risk of death among underweight persons was attenuated.

CONCLUSIONS

Excess body weight during midlife, including overweight, is associated with an increased risk of death.

A semiparametric analysis of the relationship of body mass index to mortality

OBJECTIVES

I used a semi-parametric analysis of the relationship between body mass index (BMI) and mortality to assess the adequacy of conventional BMI categories for planning public health programs to reduce mortality.

METHODS

I linked supplements from the 1987 and 1989 versions of the National Health Interview Survey to the 1995 Multiple Cause of Death File to obtain mortality information. I constructed nonlinear estimates of the association between BMI and mortality using a semiparametric regression technique.

RESULTS

The mortality risk among "normal" weight men (i.e., those in the BMI range of 20 to 25 kg/m(2)) was as high as that among men in the mild obesity category (BMIs of 30-35 kg/m(2)), with a minimum risk observed at a BMI of approximately 26 kg/m(2). Among women, the mortality risk was smallest at approximately 23 to 24 kg/m(2), with the risk increasing steadily with BMIs above 27 kg/m(2). In each specification, the slope of the line was small and volatile through the BMI range of 20 to 35 kg/m(2), suggesting negligible risk differences with minor differences in weight for much of the population.

CONCLUSIONS

Traditional BMI categories do not conform well to the complexities of the BMI-mortality relationship. In concurrence with conclusions from previous literature, I found that the current definitions of obesity and overweight are imprecise predictors of mortality risk.

Familial obesity as a proxy for omitted variables in the obesity-mortality relationship

In a conventional survival analysis of a sample of the U.S. population in 1971–1974, the association between mortality and obesity is compared with the analogous risk from the presence of an obese person in a household. The two factors have similar risk profiles, with a hazard ratio of 1.44 for nonmorbid obesity and 1.48 for nonmorbid familial obesity in one sample. If “familial obesity” cannot directly affect personal longevity, and if shared factors determine both personal and familial obesity, the mortality risk of family and actual personal obesity is similarly overstated. This false positive in the estimated risk arises from correlations among obesity and unobserved environmental, behavioral, or genetic factors.

Body mass index and mortality from ischaemic heart disease in a lean population: 10 year prospective study of 220,000 adult men

BACKGROUND

Increased body mass index (BMI) is known to be related to ischaemic heart disease (IHD) in populations where many are overweight (BMI>or=25 kg/m2) or obese (BMI>or=30). Substantial uncertainty remains, however, about the relationship between BMI and IHD in populations with lower BMI levels.

METHODS

We examined the data from a population-based, prospective cohort study of 222,000 Chinese men aged 40-79. Relative and absolute risks of death from IHD by baseline BMI were calculated, standardized for age, smoking, and other potential confounding factors.

RESULTS

The mean baseline BMI was 21.7 kg/m2, and 1942 IHD deaths were recorded during 10 years of follow-up (6.5% of all such deaths). Among men without prior vascular diseases at baseline, there was a J-shaped association between BMI and IHD mortality. Above 20 kg/m2 there was a positive association of BMI with risk, with each 2 kg/m2 higher in usual BMI associated with 12% (95% CI 6-19%, 2P=0.0001) higher IHD mortality. Below this BMI range, however, the association appeared to be reversed, with risk ratios of 1.00, 1.09, and 1.15, respectively, for men with BMI 20-21.9, 18-19.9, and <18 kg/m2. The excess IHD risk observed at low BMI levels persisted after restricting analysis to never smokers or excluding the first 3 years of follow-up, and became about twice as great after allowing for blood pressure.

CONCLUSIONS

Lower BMI is associated with lower IHD risk among people in the so-called normal range of BMI values (20-25 kg/m2), but below that range the association may well be reversed.

Blood pressure and body mass index in lean rural and semi-urban subjects in West Africa

BACKGROUND

Blood pressure (BP) is positively related to body mass index (BMI) in persons of both Caucasian and African origin, but the precise nature of the relationship is unclear.

OBJECTIVE

To study the relationship between BP and BMI in a lean African population.

DESIGN

A community-based cross-sectional study.

METHODS

The BMI and BP were measured in 362 men and 592 women aged 40-75 years living in Ashanti, Ghana. In total, 498 lived in semi-urban areas and 456 in rural villages.

RESULTS

The BMI was higher among semi-urban women [23.1 kg/m (95% confidence interval (CI), 22.5 to 23.6)] than semi-urban men [20.9 kg/m (95% CI, 20.6 to 21.5)], rural men [19.5 kg/m (95% CI, 19.1 to 19.9)] and rural women [19.9 kg/m (95% CI, 19.5 to 20.3)]. For systolic BP in women older than 52 years and in semi-urban women, the relationship was non-linear. The slope of the line below the change point ("knot") was greater than that above it. There was no evidence of non-linearity in men. For diastolic BP only younger women had a significant "knot" point at 18 kg/m. Again, the slope of the line below the "knot" was greater than that above it. In men, however, there was also evidence of a "knot" in younger and rural men, with the slope of the line below the "knot" being less that that above it (unlike in women).

CONCLUSIONS

The relationship between BP and BMI is not linear, and is possibly sigmoid, but this may vary between subgroups.

Body mass index and mortality in a middle-aged Japanese cohort

BACKGROUND: The relative risk of mortality in low and high body mass index (BMI) categories in various ethnic groups remains a controversial subject.

METHODS: To examine the relationship between BMI and mortality, a population-based prospective cohort study was conducted in two areas of Gunma Prefecture, Japan, in 1993. A total of 5,554 men and 5,827 women aged 40-69 years completed a self-administered questionnaire and were followed up until the year 2000. The hazard ratios (HRs) were estimated by the Cox proportional hazards model for different BMI classes.

RESULTS: During the seven year follow-up period, 329 men and 147 women died. As compared with those in the reference BMI category (22.0-24.9 kg/m²), men and women in the lowest BMI category (<18.5 kg/m²) had a HR (95% confidence interval [CI]) of death from all-causes of 2.66 (1.59-4.46) and 3.14 (1.38-7.13), respectively, and women in the highest BMI category (28.0+ kg/m²) had a HR of death of 3.25 (1.48-7.15), after adjusting for all possible confounding factors including smoking and after excluding deaths occurring during the first three years of follow-up.

CONCLUSION: In this prospective study of a Japanese cohort consisting of subjects ranging in age from 40 to 69 years, the curve depicting the relationship between BMI and all-cause mortality was L-shaped in men and U-shaped in women.

Body mass index and incident ischemic heart disease in South Korean men and women

Asian populations have a higher body fat percentage for a given body mass index (BMI) than Caucasians. However, little information is available on the association of BMI with ischemic heart disease (IHD) incidence in Asians at low BMI levels. The authors prospectively evaluated the association of BMI (weight (kg)/height m2) with IHD incidence over 9 years of follow-up (1993-2001) among 133,740 South Korean adults (89,050 men, 44,690 women) who participated in the 1990 and 1992 examinations of the Korea Medical Insurance Corporation Study. Average BMI at baseline was 23.4 (standard deviation, 2.3) in men and 22.3 (standard deviation, 2.3) in women. After multivariate adjustment, there was a 14% (95% confidence interval: 12, 16) increased risk of incident IHD per unit of increase in BMI. This trend was also observed within the range considered normal by Western standards, and a BMI of 24-<25 was associated with an IHD hazard ratio of 2.01 (95% confidence interval: 1.32, 3.05) in comparison with a BMI of 18-<19. The association of BMI with IHD in this cohort of relatively young South Korean men and women was progressive over the range of BMI values, with no threshold of change in risk and no indication of a U-shaped relation at low BMI levels.

Self-rated health and mortality: does the relationship extend to a low income setting?

Although a relationship between poor self-reported health status and excess mortality risk has been well-established for industrialized countries, almost no research considers developing countries. We use data from Indonesia to show that in a low-income setting, as in more advantaged parts of the world, individuals who perceive their health to be poor are significantly more likely to die in subsequent follow-up periods than their counterparts who view their health as good. This result characterizes both men and women, holds for multiple time periods, and remains after inclusion of measures of nutritional status, physical functioning, symptoms of poor physical health and depression, and hypertension. We also consider the correlates of self-rated health. Symptoms and physical functioning are strong predictors of reporting poor rather than good health, but neither these indicators nor other covariates we consider distinguish between reports of excellent rather than good health.

Body mass index and mortality in Japan: the Miyagi Cohort Study

BACKGROUND: The relation between body mass index (BMI) and mortality is not well established. The objective of this study was to examine the association in Japanese adults.

METHODS: In 1990, 18,740 men and 20,870 women in Miyagi Prefecture in rural northern Japan (40-64 years of age) completed a self-administered questionnaire including height and weight. Cox regression was used to estimate relative risk (RR) of mortality according to levels of BMI, with adjustment for age, marital status, smoking, drinking, walking, and weight change since 20 years of age.

RESULTS: During 11 years of follow-up, 1,121 men and 567 women had died. Compared with the referent BMI category (23.0-24.9), women in the highest BMI category (BMI>30.0) had a RR of death of 1.64 (95% confidence interval (CI), 1.09-2.49) and men and women in the lowest BMI categories (BMI<18.5) had a RR of death of 2.06 (95% CI, 1.49-2.84) and 1.83 (95% CI, 1.17-2.88), respectively, after adjustment for potential confounders and after exclusion of deaths occurring in the first three years of follow-up. We did not observe significant differences in mortality for subjects with wide range of BMI (18.5 or higher in men and 18.5 to 29.9 in women).

CONCLUSIONS: The risk of death from all causes increases in lean men and women, and obese women in this cohort.

Physical inactivity, excess adiposity and premature mortality

The purpose of this report is to review the evidence that physical inactivity and excess adiposity are related to an increased risk of all-cause mortality, and to better identify the independent contributions of each to all-cause mortality rates. A variance-based method of meta-analysis was used to summarize the relationships from available studies. The summary relative risk of all-cause mortality for physical activity from the 55 analyses (31 studies) that included an index of adiposity as a covariate was 0.80 [95% confidence interval (CI) 0.78-0.821, whereas it was 0.82 [95% CI 0.80-0.84] for the 44 analyses (26 studies) that did not include an index of adiposity. Thus, physically active individuals have a lower risk of mortality by comparison to physically inactive peers, independent of level of adiposity. The summary relative risk of all-cause mortality for an elevated body mass index (BMI) from the 25 analyses (13 studies) that included physical activity as a covariate was 1.23 [95% CI 1.18-1.29], and it was 1.24 [95% CI 1.21-1.28] for the 81 analyses (36 studies) that did not include physical activity as a covariate. Studies that used a measure of adiposity other than the BMI show similar relationships with mortality, and stratified analyses indicate that both physical inactivity and adiposity are important determinants of mortality risk.