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Aims: The prevalence of atrial fibrillation (AF) is positively correlated with prior cardiovascular diseases (CVD) and CVD risk factors but is lower in Chinese than Europeans despite their higher burden of CVD. We examined the prevalence and prognosis of AF and other electrocardiogram (ECG) abnormalities in the China Kadoorie Biobank. Methods and results: A random sample of 25 239 adults (mean age 59.5 years, 62% women) had a 12-lead ECG recorded and interpreted using a Mortara VERITAS™ algorithm in 2013-14. Participants were followed up for 5 years for incident stroke, ischaemic heart disease, heart failure (HF), and all CVD, overall and by CHA2DS2-VASc scores, age, sex, and area. Overall, 1.2% had AF, 13.6% had left ventricular hypertrophy (LVH), and 28.1% had ischaemia (two-thirds of AF cases also had ischaemia or LVH). The prevalence of AF increased with age, prior CVD, and levels of CHA2DS2-VASc scores (0.5%, 1.3%, 2.1%, 2.9%, and 4.4% for scores <2, 2, 3, 4, and ≥5, respectively). Atrial fibrillation was associated with two-fold higher hazard ratios (HR) for CVD (2.15; 95% CI, 1.71-2.69) and stroke (1.88; 1.44-2.47) and a four-fold higher HR for HF (3.79; 2.21-6.49). The 5-year cumulative incidence of CVD was comparable for AF, prior CVD, and CHA2DS2-VASc scores ≥ 2 (36.7% vs. 36.2% vs. 37.7%, respectively) but was two-fold greater than for ischaemia (19.4%), LVH (18.0%), or normal ECG (14.1%), respectively. Conclusion: The findings highlight the importance of screening for AF together with estimation of CHA2DS2-VASc scores for prevention of CVD in Chinese adults. [ABSTRACT FROM AUTHOR]

Background: There is an evidence gap about whether a low-risk lifestyle is as important as achieving blood pressure (BP) and random blood glucose (RBG) control. Objectives: To explore the long-term impacts and relative importance of low-risk lifestyle and health factors on the risk of all-cause and cancer mortality and macrovascular and microvascular complications among patients with diabetes. Methods: This study included 26,004 diabetes patients in the China Kadoorie Biobank. We defined 5 lifestyle factors (smoking, alcohol drinking, physical activity, fruit and vegetable intake, and waist-to-hip ratio) and 2 health factors (BP and RBG). Cox regression was used to yield adjusted hazard ratios (HRs) and CIs for individual and combined lifestyle and health factors with the risks of diabetes-related outcomes. Results: There were 5063 deaths, 6848 macrovascular complications, and 2055 microvascular complications that occurred during a median follow-up of 10.2 years. Combined low-risk lifestyle factors were associated with lower risk of all main outcomes, with HRs (95% CIs) for participants having 4 to 5 low-risk factors vs 0 to 1 of 0.50 (0.44-0.57) for all-cause mortality, 0.55 (0.43-0.71) for cancer mortality, 0.60 (0.54-0.67) for macrovascular complications, and 0.75 (0.62-0.91) for microvascular complications. The combined 4 to 5 low-risk lifestyle factors showed relative importance in predicting all-cause and cancer mortality and macrovascular complications. Conclusions: Assuming causality exists, our findings suggest that adopting a low-risk lifestyle should be regarded as important as achieving ideal BP and glycemic goals in the prevention and management of diabetes-related adverse outcomes. [ABSTRACT FROM AUTHOR]

Context: Observational studies have suggested that higher resting heart rate (RHR) may be associated with increased cardiometabolic risk. However, causal associations are not fully understood. Objective: We aimed to examine the direction, strength, and causality of the associations of RHR with cardiometabolic traits. Methods: We assessed the strength of associations between measured RHR and cardiometabolic traits in 506 211 and 372 452 participants from China Kadoorie Biobank (CKB) and UK Biobank (UKB). Mendelian randomization (MR) analyses were used to make causal inferences in 99 228 and 371 508 participants from CKB and UKB, respectively. Results: We identified significant directionally concordant observational associations between RHR and higher total cholesterol, triglycerides (TG), low-density lipoprotein, C-reactive protein (CRP), glucose, body mass index, waist-hip ratio (WHR), systolic blood pressure (SBP), and diastolic blood pressure (DBP) after the Bonferroni correction. MR analyses showed that 10 beat/min higher genetically predicted RHR was trans-ethnically associated with a higher DBP (beta 2.059 [95% CI 1.544, 2.574] mmHg in CKB; 2.037 [1.845, 2.229] mmHg in UKB), higher CRP (0.180 [0.057, 0.303] log mg/L in CKB; 0.154 [0.134, 0.174] log mg/L in UKB), higher TG (0.052 [−0.009, 0.113] log mmol/L in CKB; 0.020 [0.010, 0.030] log mmol/L in UKB) and higher WHR (0.218 [−0.033, 0.469] % in CKB; 0.225 [0.111, 0.339] % in UKB). In the opposite direction, higher genetically predicted SBP, TG, glucose, and WHR, and lower high-density lipoprotein, were associated with elevated RHR. Conclusion: Our large-scale analyses provide causal evidence for associations between RHR and cardiometabolic traits, highlighting the importance of monitoring heat rate as a means of alleviating the adverse effects of metabolic disorders. [ABSTRACT FROM AUTHOR]

Objectives: To prospectively assess the association of metabolic health status and its transition with incident diabetes risk across BMI categories. Design: Cohort study based on the China Kadoorie Biobank (CKB). Methods: The CKB study enrolled 512 715 adults aged 30–79 years from ten diverse areas in China during 2004–2008. After exclusion, 432 763 participants were cross-classified by B MI categories and the metabolic status was followed up for incident diabetes disease. The changes in BMI and metabo lic health status were defined from baseline to the second resurvey. Results: Type 2 diabetes risk is higher for metabolically healthy obese (MHO) subjects than metabolically healthy normal weight (MHN) individuals (HR: 3.97, 95% CI: 3.64–3.66), and it is highest for those affected by metabolically unhealthy obese (MUO) (HR: 6.47, 95% CI: 6.17–6.79). About 15.26% of participants with MHN converted to metabolically healthy overweight or obesity (MHOO), whereas 48.40% of MHOO remained unconverted throughout the follow-up. In obese or overweight people, the conversion from metabolically healthy to unhealthy might increase the chances of developing diabetes as compared to those with a stable metabolic healthy state (HR: 3.70, 95% CI: 2.99– 4.59), while those with persistent metabolic disorders are most likely to have diabetes (HR: 8.32, 95% CI: 7.08–9.78). Conclusions: Metabolic healthy is a transient state, and individuals converted from metabolically healthy status to unhealthy phenotypes across all BMI categories might raise the risk of diabetes. [ABSTRACT FROM AUTHOR]

Context: Observational studies have suggested that higher circulating 25-hydroxyvitamin D [25(OH)D] levels are associated with favorable serum lipids and related metabolites. However, whether such observations reflect causality remains unclear.Objective: We aimed to investigate the causal effect of elevated 25(OH)D with a detailed systemic metabolite profile in Chinese adults.Methods: A total of 225 lipid and other metabolites were quantified in 4662 individuals in the China Kadoorie Biobank. Instrumental variable analyses were performed to test the causal associations of plasma 25(OH)D with lipids and metabolites.Results: Higher plasma 25(OH)D was related to favorable lipid profiles in observational analyses. The genetic risk score was robustly correlated with observed 25(OH)D (beta[SE] = 3.54 [0.32]; P < 1 × 10-5, F-statistic = 122.3) and explained 8.4% of the variation in 25(OH)D in the Chinese population. For all individual metabolites, the causal estimates were not significant at the threshold P < 5 × 10-4 (multiple testing corrected). However, a Mendelian randomization (MR) estimate showed that per 1-SD increase in genetically determined 25(OH)D was suggestive of association with decreased levels of cholesterol, lipoprotein particles, and phospholipids within very small very low-density lipoprotein (VLDL) and intermediate-density lipoprotein (IDL) (P ≤ 0.05, nominal significance). For amino acids, fatty acids, ketone bodies, glycoprotein acetyls, fatty acids, and other traits, we did not observe any significant causal association.Conclusions: The MR analysis of metabolic data based a population-based cohort suggested a potential causal association of plasma 25(OH)D with cholesterol, lipoprotein particle, phospholipid concentrations, and total lipids within very small VLDL and IDL. Our findings highlight a long-term effect of 25(OH)D levels in maintaining healthy lipid metabolism. [ABSTRACT FROM AUTHOR]

Using data from the China Kadoorie Biobank Study, we conducted a prospective investigation on the association between type 2 diabetes mellitus (T2DM) and cancer risk in Chinese adults. A total of 508,892 participants (mean age = 51.5 (standard deviation, 10.7) years) without prior cancer diagnosis at baseline (2004-2008) were included. We documented 17,463 incident cancer cases during follow-up through December 31, 2013. Participants with T2DM had increased risks of total and certain site-specific cancers; hazard ratios were 1.13 (95% confidence interval (CI): 1.07, 1.19) for total cancer, 1.51 (95% CI: 1.29, 1.76) for liver cancer, 1.86 (95% CI: 1.43, 2.41) for pancreatic cancer, and 1.21 (95% CI: 1.01, 1.47) for female breast cancer. The associations were largely consistent when physician-diagnosed and screen-detected T2DM were analyzed separately, except for colorectal cancer (for physician-diagnosed T2DM, HR = 0.91 (95% CI: 0.73, 1.13), and for screen-detected T2DM, HR = 1.44 (95% CI: 1.18, 1.77)). In participants without a prior diagnosis of T2DM, higher random blood glucose levels were positively associated with risks of total cancer, liver cancer, and female breast cancer (all P's for trend ≤ 0.02). In conclusion, T2DM is associated with an increased risk of new-onset cancer in China, particularly cancers of the liver, pancreas, and female breast. [ABSTRACT FROM AUTHOR]

Previous studies of predominantly Western populations have reported inconsistent associations between age at menarche and risk of diabetes. We examined this relationship among Chinese women, who generally experience menarche at a later age than Western women. In 2004-2008, China Kadoorie Biobank recruited 302, 632 women aged 30-79 years from 10 areas across China, and recorded 5, 391 incident cases of diabetes during 7 years of follow-up among 270, 345 women without baseline diabetes, cardiovascular disease or cancer. Cox regression models yielded adjusted hazard ratios for incident diabetes associated with age at menarche. Overall, the mean age at menarche was 15.4 years, and decreased across successive generations. Age at menarche was linearly and inversely associated with incident diabetes, with adjusted hazard ratio of 0.96 (95% confidence interval (CI): 0.94, 0.97) per year delay. Hazard ratios were greater in younger generations (for women born in the 1960s-1970s, hazard ratio (HR) = 0.93, 95% CI: 0.90, 0.97; for women born in the 1950s, HR = 0.95, 95% CI: 0.93, 0.98; and for women born in the 1920s-1940s, HR = 0.97, 95% CI: 0.95, 0.99). Further adjustment for adulthood body mass index significantly attenuated the association (HR = 0.99, 95% CI: 0.97, 1.00), especially among those born before 1950 (HR = 1.00, 95%CI: 0.97, 1.02). Much of the inverse association between age at menarche and incident diabetes was mediated through increased adiposity associated with early menarche, especially in older generations. [ABSTRACT FROM AUTHOR]

Background: Higher fruit consumption is associated with lower risk of cardiovascular disease (CVD). Substantial uncertainties remain, however, about the associations of fruit consumption with all-cause mortality and mortality from subtypes of CVD and major non-vascular diseases, especially in China.Methods: In 2004-08, the nationwide China Kadoorie Biobank Study recruited > 0.5 million adults aged 30-79 years from 10 diverse localities in China. Fresh fruit consumption was estimated using an interviewer-administered electronic questionnaire, and mortality data were collected from death registries. Among the 462 342 participants who were free of major chronic diseases at baseline, 17 894 deaths were recorded during ∼ 7 years of follow-up. Cox regression yielded adjusted rate ratios (RRs) for all-cause and cause-specific mortality associated with fruit consumption.Results: At baseline, 28% of participants reported consuming fruit ≥ 4 days/week (regular consumers) and 6% reported never/rarely consuming fruit (non-consumers). Compared with non-consumers, regular consumers had 27% [RR = 0.73, 95% confidence interval (CI) 0.70-0.76] lower all-cause mortality, 34% lower CVD mortality (n = 6166; RR = 0.66, 0.61-0.71), 17% lower cancer mortality (n = 6796; RR = 0.83, 0.78-0.89) and 42% lower mortality from chronic obstructive pulmonary disease (COPD) (n = 1119; RR = 0.58, 0.47-0.71). For each of the above, there was an approximately log-linear dose-response relationship with amount consumed. For mortality from site-specific cancers, fruit consumption was inversely associated with digestive tract cancer (n = 2265; RR = 0.72, 0.64-0.81), particularly oesophageal cancer (n = 801; RR = 0.65, 0.50-0.83), but not with cancer of lung or liver.Conclusions: Among Chinese adults, higher fresh fruit consumption was associated with significantly lower mortality from several major vascular and non-vascular diseases. Given the current low population level of fruit consumption, substantial health benefits could be gained from increased fruit consumption in China. [ABSTRACT FROM AUTHOR]

Background: Simultaneously adhering to multiple healthy lifestyle factors has been related to up to 90% reduction in type 2 diabetes (T2DM) incidence in White populations; however, little is known about whether such protective effects persist in other non-White populations.Methods: We examined the associations of six lifestyle factors with T2DM in the China Kadoorie Biobank of 461 211 participants aged 30-79 years without diabetes, cardiovascular diseases or cancer at baseline. We defined low-risk lifestyle factors as non-smoking or having stopped for reasons other than illness; alcohol consumption of <30 g/day; upper quarter of the physical activity level; diet rich in vegetables and fruits, low in red meat and with some degree of replacement of rice with wheat; body mass index (BMI) of 18.5-23.9 kg/m2; and waist-to-hip ratio (WHR) <0.90 (men)/<0.85 (women).Results: During a median of 7.2 years of follow-up, we identified 8784 incident T2DM. In multivariable-adjusted analyses, two important risk factors for developing T2DM were higher BMI and WHR. Compared with participants without any low-risk factors, the hazard ratio [95% confidence interval (CI)] for those with at least three low-risk factors was 0.20 (0.19, 0.22). Approximately 72.6% (64.2%, 79.3%) of the incident diabetes were attributable to the combination of BMI, WHR, diet and physical activity. The population attributable risk percentage (PAR%) of diabetes appeared to be similar for men and women, and higher among urban, older and obese participants.Conclusions: Our findings indicate that adherence to a healthy lifestyle may substantially lower the burden of T2DM in the Chinese population. [ABSTRACT FROM AUTHOR]

Background: Adiposity is increasing rapidly in China but little is known about the relevance to it of women's reproductive factors, which differ inter-generationally and from that in the West. We assess associations of adiposity with life-course reproductive factors in Chinese women.Methods: In 2004-08, the nationwide China Kadoorie Biobank recruited 303 000 women aged 30-79 (mean 50) years from 10 diverse regions. Multivariable linear regression was used to examine associations of reproductive factors (e.g. age at menarche/first birth/menopause, parity, breastfeeding and reproductive years) with measures of general [e.g. body mass index (BMI)] and central [e.g. waist circumference (WC)] adiposity in adulthood.Results: Overall, the mean BMI was 23.7 (standard deviation 3.3) kg/m 2 , mean age at menarche was 15 (2) years and nearly all had given birth (99%) and breastfed children (98%). Adiposity was associated inversely with age at menarche and at first birth, with 0.19 and 0.05 kg/m 2 lower BMI and 0.38 and 0.12 cm lower WC per 1-year delay respectively ( P  < 0.001). Among 128 259 post-menopausal women, adiposity was associated positively with age at menopause and reproductive years, with 0.05 and 0.07 kg/m 2 higher BMI and 0.12 and 0.17 cm higher WC per 1-year increase, respectively ( P  < 0.001). The proportion with overweight/obesity had similar associations with these reproductive factors. Adiposity had a non-linear positive association with parity, but no association with breastfeeding duration.Conclusion: Among Chinese women, earlier age at menarche and at first birth, later age at menopause and longer reproductive years were independently associated with increased adiposity late in life. [ABSTRACT FROM AUTHOR]

Background: Women's parity has been associated with risk of cardiovascular disease (CVD). It is unclear, however, whether it reflects biological effects of childbearing or uncontrolled socio-economic and lifestyle factors associated with childrearing. We assessed the association between number of children and incident CVD outcomes separately in women and men.Methods: In 2004-08, the nationwide China Kadoorie Biobank recruited 0.5 million individuals aged 30-79 years from 10 diverse regions. During 7 years of follow-up, 24 432 incident cases of coronary heart disease (CHD) and 35 736 of stroke were recorded among 489 762 individuals without prior CVD. Multivariable Cox regression models were used to estimate sex-specific hazard ratios (HRs) and 95% confidence intervals (CIs) for CHD and stroke associated with number of children.Results: Overall, 98% of all participants had children and the mean number of children declined progressively from four in older participants to one or two in younger participants. Compared with childless women, women with children had an increased risk of CHD, but not of stroke [HR (95% CI): 1.14 (1.00; 1.30) and 1.03 (0.92; 1.16)]. Corresponding results for men were 1.20 (1.06; 1.35) and 1.13 (1.03; 1.24), respectively. In individuals with children, there was a log-linear association between number of children and CVD outcomes; in women, each additional child was associated with adjusted HRs of 1.02 (1.01; 1.04) for CHD and 1.02 (1.01; 1.03) for stroke, similar in magnitude to that in men [1.03 (1.01; 1.04) for CHD and 1.02 (1.01; 1.03) for stroke].Conclusion: In Chinese adults, the association between the number of children and risk of CHD and stroke was similar between men and women, suggesting that factors associated with parenthood and childrearing are more likely to affect the risk of CVD outcomes than factors associated with childbearing. [ABSTRACT FROM AUTHOR]

Background: Lipoprotein-associated phospholipase A2 (Lp-PLA2) has been implicated in development of atherosclerosis; however, recent randomized trials of Lp-PLA2 inhibition reported no beneficial effects on vascular diseases. In East Asians, a loss-of-function variant in the PLA2G7 gene can be used to assess the effects of genetically determined lower Lp-PLA2 METHODS: PLA2G7 V279F (rs76863441) was genotyped in 91 428 individuals randomly selected from the China Kadoorie Biobank of 0.5 M participants recruited in 2004-08 from 10 regions of China, with 7 years' follow-up. Linear regression was used to assess effects of V279F on baseline traits. Logistic regression was conducted for a range of vascular and non-vascular diseases, including 41 ICD-10 coded disease categories.Results: PLA2G7 V279F frequency was 5% overall (range 3-7% by region), and 9691 (11%) participants had at least one loss-of-function variant. V279F was not associated with baseline blood pressure, adiposity, blood glucose or lung function. V279F was not associated with major vascular events [7141 events; odds ratio (OR) = 0.98 per F variant, 95% confidence interval (CI) 0.90-1.06] or other vascular outcomes, including major coronary events (922 events; 0.96, 0.79-1.18) and stroke (5967 events; 1.00, 0.92-1.09). Individuals with V279F had lower risks of diabetes (7031 events; 0.91, 0.84-0.98) and asthma (182 events; 0.53, 0.28-0.98), but there was no association after adjustment for multiple testing.Conclusions: Lifelong lower Lp-PLA2 activity was not associated with major risks of vascular or non-vascular diseases in Chinese adults. Using functional genetic variants in large-scale prospective studies with linkage to a range of health outcomes is a valuable approach to inform drug development and repositioning. [ABSTRACT FROM AUTHOR]

Objectives: The distinction between metastatic breast carcinomas (BCs) and primary lung carcinomas (PLCs) can be difficult. This study tested the utility of trefoil factor 1 (TFF1) for this purpose and compared it with mammaglobin and GATA protein binding 3 (GATA-3). Methods: Tissue microarrays containing 365 BCs and 338 PLCs were stained with TFF1, mammaglobin, and GATA-3, and an H-score was calculated. Sensitivity, specificity, and accuracy were calculated, and logistical regression analysis was performed. Results: Accuracy of correctly classifying the tumor type was 81.9%, 71.3%, and 64.0% for GATA-3, mammaglobin, and TFF1, respectively. Odds ratios for selecting BCs were 25.69, 93.15, and 4.17, respectively, with P values less than .001. With a single exception, the best immunopanel included GATA-3 and mammaglobin in all comparisons. Conclusions: TFF1 demonstrated breast specificity but was inferior to mammaglobin and GATA-3. Therefore, its routine clinical use may not be justified. TFF1 showed little benefit when added to an immunopanel. [ABSTRACT FROM AUTHOR]

Background: Greater adiposity is associated with higher blood pressure. Substantial uncertainty remains, however, about which measures of adiposity most strongly predict blood pressure and whether these associations differ materially between populations.Methods: We examined cross-sectional data on 500 000 adults recruited from 10 diverse localities across China during 2004-08. Multiple linear regression was used to estimate the effects on systolic blood pressure (SBP) of general adiposity [e.g. body mass index (BMI), body fat percentage, height-adjusted weight] vs central adiposity [e.g. waist circumference (WC), hip circumference (HC), waist-hip ratio (WHR)], before and after adjustment for each other. The main analyses excluded those reported taking any antihypertensive medication, and were adjusted for age, region and education.Results: The overall mean [standard deviation (SD)] BMI was 23.6 (3.3) kg/m(2) and mean WC was 80.0 (9.5) cm. The differences in SBP (men/women, mmHg) per 1SD higher general adiposity (height-adjusted weight: 6.6/5.6; BMI: 5.5/4.9; body fat percentage: 5.5/5.0) were greater than for central adiposity (WC: 5.0/4.3; HC: 4.8/4.1; WHR: 3.7/3.2), with a 10 kg/m(2) greater BMI being associated on average with 16 (men/women: 17/14) mmHg higher SBP. The associations of blood pressure with measures of general adiposity were not materially altered by adjusting for WC and HC, but those for central adiposity were significantly attenuated after adjusting for BMI (WC: 1.1/0.7; HC: 0.3/-0.2; WHR: 0.6/0.6).Conclusion: In adult Chinese, blood pressure is more strongly associated with general adiposity than with central adiposity, and the associations with BMI were about 50% stronger than those observed in Western populations. [ABSTRACT FROM AUTHOR]

Introduction Blood pressure is a major cause of cardiovascular disease (CVD) and both may increase as outdoor temperatures fall. However, there are still limited data about seasonal variation in blood pressure and CVD mortality among patients with prior-CVD. Methods We analysed dataon 23 000 individuals with prior-CVDwhowere recruited from10 diverse regions into the China Kadoorie Biobank during 2004-8. After 7 years of follow-up, 1484 CVD deaths were recorded. Baseline survey datawere used to assess seasonal variation in systolic blood pressure (SBP) and its association with outdoor temperature. Coxregression was used to examine the association of usual SBP with subsequent CVD mortality, and seasonal variation in CVD mortality was assessed by Poisson regression. All analyses were adjusted for age, sex, and region. Results Mean SBP was significantly higher in winter than in summer (145 vs. 136 mmHg, P < 0.001), especially among those without central heating. Above 5°C, each 10°C lower outdoor temperature was associated with 6.2 mmHg higher SBP. Systolic blood pressure predicted subsequent CVD mortality, with each 10 mmHg higher usual SBP associated with 21% (95% confidence interval: 16-27%) increased risk. Cardiovascular disease mortality varied by season, with 41% (21-63%) higher risk in winter compared with summer. Conclusion Among adult Chinese with prior-CVD, there is both increased blood pressure and CVD mortality in winter. Careful monitoring and more aggressive blood pressure lowering treatment in the cold months are needed to help reduce the winter excess CVD mortality in high-risk individuals. [ABSTRACT FROM AUTHOR]

Background: Low body mass index (BMI) is associated with chronic obstructive pulmonary disease (COPD) in populations where many are overweight. Substantial uncertainty remains about the relationship in populations with lower mean BMI levels, and about the relevance to it of the effects of smoking or of reverse causality.Methods: A nationally representative prospective cohort study included 221,194 Chinese men aged 40-79 years in 1990-91, who were followed up for 15 years or to the age of 80 years. Hazard ratios for COPD-related mortality vs baseline BMI were adjusted for age, smoking, drinking and other factors. To reduce reverse causality, main analyses excluded all men with prior history of any respiratory diseases or abnormal lung function at baseline, leaving 2960 COPD-related deaths (16% of all deaths).Results: The mean baseline BMI was 21.7 kg/m(2). There was a highly significant inverse association between BMI and COPD-related mortality among men without any apparent impairment of lung function. Approximately 90% of men had a baseline BMI <25 kg/m(2), and among them, 5 kg/m(2) lower BMI was associated with 31% (95% confidence interval 18-45%) higher COPD-related mortality. The excess risk persisted after restricting the analysis to never-smokers or excluding the first 5 years of follow-up.Conclusions: Low BMI is associated with increased COPD mortality in a relatively lean adult male population in China where COPD is one of the most common causes of death. [ABSTRACT FROM AUTHOR]

Background Increased body mass index (BMI) is known to be related to ischaemic heart disease (IHD) in populations where many are overweight (BMI ≥ 25 kg/m2) or obese (BMI ≥ 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. [ABSTRACT FROM AUTHOR]