Adiposity and incident diabetes within 4 years of follow-up: the Guangzhou Biobank Cohort Study

An early prediction model for type 2 diabetes mellitus based on genetic variants and nongenetic risk factors in a Han Chinese cohort

Aims

We aimed to construct a prediction model of type 2 diabetes mellitus (T2DM) in a Han Chinese cohort using a genetic risk score (GRS) and a nongenetic risk score (NGRS).

Methods

A total of 297 Han Chinese subjects who were free from type 2 diabetes mellitus were selected from the Tianjin Medical University Chronic Disease Cohort for a prospective cohort study. Clinical characteristics were collected at baseline and subsequently tracked for a duration of 9 years. Genome-wide association studies (GWASs) were performed for T2DM-related phenotypes. The GRS was constructed using 13 T2DM-related quantitative trait single nucleotide polymorphisms (SNPs) loci derived from GWASs, and NGRS was calculated from 4 biochemical indicators of independent risk that screened by multifactorial Cox regressions.

Results

We found that HOMA-IR, uric acid, and low HDL were independent risk factors for T2DM (HR >1; P<0.05), and the NGRS model was created using these three nongenetic risk factors, with an area under the ROC curve (AUC) of 0.678; high fasting glucose (FPG >5 mmol/L) was a key risk factor for T2DM (HR = 7.174, P< 0.001), and its addition to the NGRS model caused a significant improvement in AUC (from 0.678 to 0.764). By adding 13 SNPs associated with T2DM to the GRS prediction model, the AUC increased to 0.892. The final combined prediction model was created by taking the arithmetic sum of the two models, which had an AUC of 0.908, a sensitivity of 0.845, and a specificity of 0.839.

Conclusions

We constructed a comprehensive prediction model for type 2 diabetes out of a Han Chinese cohort. Along with independent risk factors, GRS is a crucial element to predicting the risk of type 2 diabetes mellitus.

Association of obesity profiles with type 2 diabetes in Chinese adults: Findings from the China health and nutrition survey

Aims

To examine longitudinal associations of obesity profiles, continuous BMI, and waist circumference (WC) with the risk of type 2 diabetes in Chinese adults.

Methods

Data were derived from three waves (2009, 2015, and 2018) of the China Health and Nutrition Survey, and 3,595 adults aged 18–65 years who participated in at least two waves of the survey and had completed data were analyzed. Obesity profiles included BMI- or WC-related single obesity and combined obesity. Combined obesity was categorized into six groups including Group 1 with normal BMI and WC, Group 2 with normal BMI but pre-abdominal obesity, Group 3 with normal BMI but abdominal obesity, Group 4 with abnormal BMI (overweight and general obesity) and normal WC, Group 5 with abnormal BMI and pre-abdominal obesity, and Group 6 with abnormal BMI and abdominal obesity. Three-level mixed-effects logistic regressions with random intercept stratified by gender and restricted cubic splines were performed to examine ORs and 95%CIs for the risk of type 2 diabetes.

Results

In men, compared with subjects of Group 1, those in Group 3 had higher risk, with an OR of 4.83 (95% CI: 1.99–11.74), followed by those in Group 6 (OR = 4.05, 95%CI: 2.32–7.08) and Group 5 (OR = 2.98, 95%CI: 1.51–5.87) after adjusting for all potential confounders. For women, the subject of Group 6 had highest risk (OR = 8.79, 95%CI: 4.04–19.12), followed by Group 3 (OR = 3.30, 95%CI: 1.23–8.86) and Group 5 (OR = 3.16, 95%CI: 1.21–8.26). No significant association between abnormal BMI and normal WC (Group 4) was observed in both genders. Type 2 diabetes risk increased steeply at BMI of 23.5 kg/m2 and 22.5 kg/m2 or higher, and WC of 82.0 cm and 83.0 cm or higher in Chinese adult men and women, respectively (p for overall &lt;0.001).

Conclusion

Chinese adults with pre-abdominal or abdominal obesity had a relative high risk of type 2 diabetes independent of BMI levels. Lower BMI (≤23.5 kg/m2 for men and ≤22.5 kg/m2 for women) and lower WC (82.0 cm for men and ≤83.0 cm for women) values than the current Chinese obesity cut-offs were found to predict the risk of type 2 diabetes. These findings urge to inform WC modification and optimization of early screening guidelines.

Impact of Older Age Adiposity on Incident Diabetes: A Community-Based Cohort Study in China

BACKGROUND

Obesity classifications vary globally and the impact of older age adiposity on incident diabetes has not been well-studied.

METHODS

We examined a random sample of 2,809 participants aged ≥60 years in China, who were free of diabetes at baseline and were followed up for up to 10 years to document diabetes (n=178). The incidence of diabetes was assessed in relation to different cut-off points of body mass index (BMI) and waist circumference (WC) in multiple adjusted Cox regression models.

RESULTS

The diabetic risk in the cohort increased linearly with the continuous and quartile variables of BMI and WC. The BMI-World Health Organization (WHO) and BMI-China criteria analysis did not show such a linear relationship, however, the BMI-Asian/Hong Kong criteria did; adjusted hazards ratio (HR) was 0.42 (95% confidence interval [CI], 0.20 to 0.90) in BMI <20 kg/m2, 1.46 (95% CI, 0.99 to 2.14) in 23-≤26 kg/m2, and 1.63 (95% CI, 1.09 to 2.45) in ≥26 kg/m2. The WC-China criteria revealed a slightly better prediction of diabetes (adjusted HRs were 1.79 [95% CI, 1.21 to 2.66] and 1.87 [95% CI, 1.22 to 2.88] in central obese action levels 1 and 2) than the WC-WHO. The combination of the BMI-Asian/Hong Kong with WC-China demonstrated the strongest prediction. There were no gender differences in the impact of adiposity on diabetes.

CONCLUSION

In older Chinese, BMI-Asian/Hong Kong criteria is a better predictor of diabetes than other BMI criterion. Its combination with WC-China improved the prediction of adiposity to diabetes, which would help manage bodyweight in older age to reduce the risk of diabetes.

Excess Body Mass-A Factor Leading to the Deterioration of COVID-19 and Its Complications-A Narrative Review

Currently, the world is facing two serious pandemics: obesity and COVID-19. It is well-established that the prevalence of obesity has risen dramatically, causing a deterioration in the health quality of the population and increasing susceptibility for the unfavourable course of acute infections. It has been observed that excess body mass significantly influences the COVID-19 outcome. The aim of this review is to present the latest scientific reports on the impact of excess body mass on the course and complications of COVID-19. The Web of Science, PubMed, and Google Scholar databases were searched. Only studies reporting patients stated to be COVID-19 positive based on the results of a nasopharyngeal swab and the ribonucleic acid test were included. It is shown that thromboembolic and ischemic complications, namely stroke, disseminated intravascular coagulation, severe hyperglycaemia, and leukoencephalopathy are more likely to appear in COVID-19 positive patients with obesity compared to non-obese subjects. COVID-19 complications such as cardiomyopathy, dysrhythmias, endothelial dysfunction, acute kidney injury, dyslipidaemia, lung lesions and acute respiratory distress syndrome have a worse outcome among obese patients.

Association of fish consumption with risk of all-cause and cardiovascular disease mortality: an 11-year follow-up of the Guangzhou Biobank Cohort Study

BACKGROUND

Whether fish consumption is associated with all-cause, cardiovascular (CVD), ischemic heart disease (IHD) and stroke mortality remains inconclusive. We examined the association of fish consumption with all-cause, cardiovascular (CVD), ischemic heart disease (IHD) and stroke mortality in older men and women in south China.

METHODS

A total of 18,215 participants including men and women without CVD at baseline (2003-2006) from Guangzhou Biobank Cohort Study (GBCS) were included and followed up till December 2017. Deaths were identified through record linkage with the Death Registry. Information on fish consumption was obtained using a food frequency questionnaire.

RESULTS

During an average follow-up of 11.4 (standard deviation = 2.1) years, 2,697 deaths occurred, including 917 total CVD, 397 IHD and 374 stroke deaths. After adjusting for potential confounders, compared with fish consumption of 0-3 servings/week (i.e., 0-21 g/day, one serving = 50 g), consumption of 4-6 servings/week (29-43 g/day) showed significantly lower risks of all-cause and CVD mortality (hazards ratio (HR) and 95% confidence interval (CI): 0.85 (0.76, 0.95) and 0.77 (0.64, 0.93), respectively), but the reduced risk of IHD mortality (HR (95% CI): 0.80 (0.60, 1.07)) was not significant. Consumption of 7-10 servings/week or higher showed no association with all-cause, CVD, IHD, and stroke mortality.

CONCLUSIONS

Moderate fish consumption of 4-6 servings/week (29-43 g/day) was associated with lower all-cause and CVD mortality risk. Our findings support the current general advice on regular fish consumption also in middle-aged and older adults.

Mortality in relation to changes in physical activity in middle-aged to older Chinese: An 8-year follow-up of the Guangzhou Biobank Cohort Study

BACKGROUND

Physical activity (PA) is generally encouraged. Studies from developed countries in the West have shown that maintenance of adequate PA or increasing PA are associated with lower mortality risk. It is unclear whether these associations apply to an older Chinese population. Hence, we examined the changes in PA prospectively among a middle-aged and older Chinese population over an average of 4 years and explored their subsequent mortality risks.

METHODS

Metabolic equivalent scores of PA among participants in the Guangzhou Biobank Cohort Study were calculated. Participants were divided into 3 groups related to PA level, and changes in PA were classified into 9 categories. Information on vital status and causes of death from March 2008 to December 2012 (the first repeated examination) until December 31, 2017, was obtained via record linkage with the Death Registry.

RESULTS

Of 18,104 participants aged 61.21 ± 6.85 years (mean ± SD), 1461 deaths occurred within 141,417 person-years. Compared to participants who maintained moderate PA, those who decreased PA from moderate or high levels to a low level had increased risks for all-cause mortality (hazard ratio (HR) = 1.47, 95% confidence interval (95%CI): 1.11-1.96). Participants who maintained a high level of PA (HR = 0.83, 95%CI: 0.70-0.98) or increased PA from low to high levels (HR = 0.71, 95%CI: 0.52-0.97) showed lower all-cause mortality risks. Those who maintained low PA levels showed a higher all-cause mortality risk, whereas those who increased their PA levels showed a non-significantly lower risk. Similar results were found for cardiovascular disease risk.

CONCLUSION

Even at an older age, maintaining a high PA level or increasing PA from low to high levels results in lower mortality risks, suggesting that substantial health benefits might be achieved by maintaining or increasing engagement in adequate levels of PA. The increased risk of maintaining a low PA level or decreasing PA to a low level warrants the attention of public health officials and clinicians.

Association of adiposity with diabetes: A national research among Chinese adults

BACKGROUND

Adiposity is an established risk factor for diabetes. The different measurements of adiposity for predicting diabetes have been compared in recent studies in Western countries. However, similar researches among Chinese adults are limited.

METHODS

Data were collected from a national survey conducted during September 2014 and May 2015 Among Chinese adults aged 40 years and older across 30 China's provinces. Multilevel model analysis was performed to examine the impacts of different obesity indices [body mass index (BMI), waist circumference (WC), lipid accumulation product index (LAP), visceral adiposity index (VAI), and body adiposity index (BAI)] on the risk of diabetes.

RESULTS

A total of 162 880 participants were included in this study. Of them, 54.47% were female. With an increase in BMI, WC, LAP, VAI, and BAI, the prevalence of diabetes significantly grew (P < 0.001). The multilevel model analysis showed that WC has the strongest impact on diabetes prevalence, while BAI was the weakest. For one SD increment in BMI, WC, LAP, VAI, and BAI, the prevalence of diabetes increased by 27.0% (Odds Ratio (OR) = 1.270, 95% Confidence interval (CI) = 1.251-1.289), 37.4% (OR = 1.374, 95% CI = 1.346-1.401), 28.1% (OR = 1.281, 95% CI = 1.266-1.297), 22.0% (OR = 1.220, 95% CI = 1.204-1.236), and 17.4% (OR = 1.174, 95% CI = 1.151-1.192), respectively.

CONCLUSION

Obesity indicators of BMI, WC, LAP, VAI, and BAI have significant positive relationships with the risk of diabetes. WC has the strongest impact on diabetes, while BAI has the weakest.

Obesity and diabetes as high-risk factors for severe coronavirus disease 2019 (Covid-19)

The outbreak of the coronavirus disease 2019 (Covid-19) has become an evolving worldwide health crisis. With the rising prevalence of obesity and diabetes has come an increasing awareness of their impacts on infectious diseases, including increased risk for various infections, post-infection complications and mortality from critical infections. Although epidemiological and clinical characteristics of Covid-19 have been constantly reported, no article has systematically illustrated the role of obesity and diabetes in Covid-19, or how Covid-19 affects obesity and diabetes, or special treatment in these at-risk populations. Here, we present a synthesis of the recent advances in our understanding of the relationships between obesity, diabetes and Covid-19 along with the underlying mechanisms, and provide special treatment guidance for these at-risk populations.

Adiposity change and mortality in middle-aged to older Chinese: an 8-year follow-up of the Guangzhou Biobank Cohort Study

OBJECTIVE

To examine the associations of change in body mass index (BMI) and waist circumference (WC) over an average of 4 years with subsequent mortality risk in middle-aged to older Chinese.

DESIGN

Prospective cohort study based on the Guangzhou Biobank Cohort Study.

SETTING

Community-based sample.

PARTICIPANTS

17 773 participants (12 956 women and 4817 men) aged 50+ years.

PRIMARY AND SECONDARY OUTCOME MEASURES

Primary outcome measure was all-cause mortality. Secondary outcome measures were cardiovascular disease (CVD) and cancer mortality. Causes of death were obtained via record linkage, and coded according to the International Classification of Diseases (tenth revision).

RESULTS

1424 deaths (53.4% women) occurred in the 17 773 participants (mean age 61.2, SD 6.8 years) during an average follow-up of 7.8 (SD=1.5) years, and 97.7% of participants did not have an intention of weight loss . Compared with participants with stable BMI, participants with BMI loss (>5%), but not gain, had a higher risk of all-cause mortality (HR=1.49, 95% CI 1.31 to 1.71), which was greatest in those who were underweight (HR=2.45, 95% CI 1.31 to 4.59). Similar patterns were found for WC. In contrast, for participants with a BMI of ≥27.5 kg/m², BMI gain, versus stable BMI, was associated with 89% higher risk of all-cause mortality (HR=1.89, 95% CI 1.25 to 2.88), 72% higher risk of CVD mortality (HR=1.72, 95% CI 0.80 to 3.72) and 2.27-fold risk of cancer mortality (HR=2.27, 95% CI 1.26 to 4.10).

CONCLUSION

In older people, unintentional BMI/WC loss, especially in those who were underweight was associated with higher mortality risk. However, BMI gain in those with obesity showed excess risks of all-cause and cancer mortality, but not CVD mortality. Frequent monitoring of changes in body size can be used as an early warning for timely clinical investigations and interventions and is important to inform appropriate health management in older Chinese.

Coronavirus disease 2019 (COVID-19) and obesity. Impact of obesity and its main comorbidities in the evolution of the disease

The COVID-19 pandemic is posing a great challenge worldwide. Its rapid progression has caused thousands of deaths worldwide. Although multiple aspects remain to be clarified, some risk factors associated with a worse prognosis have been identified. These include obesity and some of its main complications, such as diabetes and high blood pressure. Furthermore, although the possible long-term complications and psychological effects that may appear in survivors of COVID-19 are not well known yet, there is a concern that those complications may be greater in obese patients. In this manuscript, we review some of the data published so far and the main points that remain to be elucidated are emphasized.

Obesity and COVID-19 Severity in a Designated Hospital in Shenzhen, China

OBJECTIVE

Patients with obesity are at increased risk of exacerbations from viral respiratory infections. However, the association of obesity with the severity of coronavirus disease 2019 (COVID-19) is unclear. We examined this association using data from the only referral hospital in Shenzhen, China.

RESEARCH DESIGN AND METHODS

A total of 383 consecutively hospitalized patients with COVID-19 admitted from 11 January 2020 to 16 February 2020 and followed until 26 March 2020 at the Third People's Hospital of Shenzhen were included. Underweight was defined as a BMI <18.5 kg/m², normal weight as 18.5-23.9 kg/m², overweight as 24.0-27.9 kg/m², and obesity as ≥28 kg/m².

RESULTS

Of the 383 patients, 53.1% were normal weight, 4.2% were underweight, 32.0% were overweight, and 10.7% were obese at admission. Obese patients tended to have symptoms of cough (P = 0.03) and fever (P = 0.06) compared with patients who were not obese. Compared with normal weight patients, those who were overweight had 1.84-fold odds of developing severe COVID-19 (odds ratio [OR] 1.84, 95% CI 0.99-3.43, P = 0.05), while those who were obese were at 3.40-fold odds of developing severe disease (OR 3.40, 95% CI 1.40-2.86, P = 0.007), after adjusting for age, sex, epidemiological characteristics, days from disease onset to hospitalization, presence of hypertension, diabetes, cardiovascular disease, chronic obstructive pulmonary disease, liver disease, and cancer, and drug used for treatment. Additionally, after similar adjustment, men who were obese versus those who were normal weight were at increased odds of developing severe COVID-19 (OR 5.66, 95% CI 1.80-17.75, P = 0.003).

CONCLUSIONS

In this study, obese patients had increased odds of progressing to severe COVID-19. As the severe acute respiratory syndrome coronavirus 2 may continue to spread worldwide, clinicians should pay close attention to obese patients, who should be carefully managed with prompt and aggressive treatment.

Assessing different anthropometric indices and their optimal cutoffs for prediction of type 2 diabetes and impaired fasting glucose in Asians: The Jinchang Cohort Study

BACKGROUND

To study the association between anthropometric measurements and the risk of diabetes and impaired fasting glucose (IFG) and compare body mass index (BMI), waist circumference (WC), and waist-to-height ratio (WHtR) to determine the best indicator and its optimal cutoffs for predicting type 2 diabetes and IFG.

METHODS

A Chinese prospective (2011-2019) cohort named the Jingchang cohort that included 48 001 participants was studied. Using Cox proportional hazard models, hazard ratios (HRs) for incident type 2 diabetes or IFG per 1 SD change in BMI, WC, and WHtR were calculated. Area under the curve (AUC) was compared to identify the best anthropometric variable and its optimal cutoff for predicting diabetes.

RESULTS

The association of BMI, WC, and WHtR with type 2 diabetes or IFG risk was positive in the univariate and multivariable-adjusted Cox proportional hazard models. Of all three indexes, the AUC of BMI was largest and that of WC was smallest. The derived cutoff values for BMI, WC, and WHtR were 24.6 kg/m² , 89.5 cm, and 0.52 in men and 23.4 kg/m² , 76.5 cm, and 0.47 in women for predicting diabetes, respectively. The derived cutoff values for BMI, WC, and WHtR were 23.4 kg/m² , 87.5 cm, and 0.50 in men and 22.5 kg/m² , 76.5 cm, and 0.47 in women for predicting IFG, respectively. [Correction added on 14 April 2020, after first online publication: '0' has been deleted from 'WC,0' in the first sentence.].

CONCLUSIONS

Our derived cutoff points were lower than the values specified in the most current Asian diabetes guidelines. We recommend a cutoff point for BMI in Asians of 23 kg/m² and for WC a cutoff point of 89 cm in men and 77 cm in women to define high-risk groups for type 2 diabetes; screening should be considered for these populations.

Waist Circumference and its Changes Are More Strongly Associated with the Risk of Type 2 Diabetes than Body Mass Index and Changes in Body Weight in Chinese Adults

BACKGROUND

The associations of different adiposity indicators and short-term adiposity change with diabetes risk are not fully elucidated.

OBJECTIVE

We aimed to assess the independent and joint effects of different baseline adiposity indicators and short-term body adiposity change on the risk of type 2 diabetes.

METHODS

We prospectively followed 10,419 Chinese adults aged 20-80 y in 2008-2012. Incident diabetes was diagnosed based on fasting glucose, 2-h glucose, or glycated hemoglobin (HbA1c) after an oral glucose tolerance test using the American Diabetes Association standard. Cox proportional hazard regression models were used to assess the associations of adiposity indicators and adiposity change with diabetes risk.

RESULTS

During a mean follow-up of 2.8 y, we identified 805 type 2 diabetes cases. Baseline BMI, waist circumference, and waist-height ratio (WHtR) were all positively associated with diabetes risk. The area under the curve was significantly greater for waist circumference (0.624) and WHtR (0.627) than for BMI (0.608) (P <0.05). Compared with subjects with stable adiposity levels (±2 kg or ± 3 cm in changes in body weight or waist circumference) from baseline to Year 1, those subjects with the most weight gain or the most waist circumference gain had a 1.53-fold or 1.37-fold greater risk of diabetes; those with the most weight loss had a 46% lower risk of diabetes. Furthermore, regardless of baseline weight status, weight or waist circumference change in the first year was associated with diabetes risk.

CONCLUSION

Abdominal adiposity indicators, waist circumference and its change, are more strongly associated with the risk of type 2 diabetes than general adiposity indicators, BMI, and changes in body weight among Chinese adults.

Glycemic Measures and Risk of Mortality in Older Chinese: The Guangzhou Biobank Cohort Study

CONTEXT

China has the largest number of people with type 2 diabetes mellitus (T2DM) in the world. Data from previous studies have suggested that up to one-fifth of individuals with diabetes would be missed without an oral glucose tolerance test (OGTT). To date, there is little information on the mortality risk of these individuals.

OBJECTIVE

We estimated the association of different indicators of hyperglycemia with mortality in the general Chinese population.

DESIGN

Prospective cohort study.

SETTING

China.

PARTICIPANTS

A total of 17 939 participants aged 50+ years.

EXPOSURES

Previously diagnosed diabetes and newly detected diabetes defined by fasting glucose (≥7.0 mmol/L), 2-hour postload glucose (≥11.1 mmol/L), or hemoglobin A1c (HbA1c, ≥6.5%).

MAIN OUTCOMES MEASURES

Deaths from all-cause, cardiovascular disease, and cancer were identified by record linkage with death registration.

RESULTS

During 7.8 (SD, 1.5) years' follow-up, 1439 deaths were recorded. Of 3706 participants with T2DM, 2126 (57%) had known T2DM, 118 (3%) were identified by isolated elevated fasting glucose, 1022 (28%) had isolated elevated postload glucose, and 440 (12%) had both elevated fasting and postload glucose. Compared with normoglycemia, the hazard ratio (95% confidence interval) of all-cause mortality was 1.71 (1.46-2.00), 0.96 (0.47-1.93), 1.43 (1.15-1.78), and 1.82 (1.35-2.45) for the 4 groups, respectively. T2DM defined by elevated HbA1c was not significantly associated with all-cause mortality (hazard ratio, 1.17; 95% confidence interval, 0.81-1.69).

CONCLUSION

Individuals with isolated higher 2-h postload glucose had a higher risk of mortality by 43% than those with normoglycemia. Underuse of OGTT leads to substantial underdetection of individuals with a higher mortality risk and lost opportunities for early intervention.

The eMERGE genotype set of 83,717 subjects imputed to ~40 million variants genome wide and association with the herpes zoster medical record phenotype

The Electronic Medical Records and Genomics (eMERGE) network is a network of medical centers with electronic medical records linked to existing biorepository samples for genomic discovery and genomic medicine research. The network sought to unify the genetic results from 78 Illumina and Affymetrix genotype array batches from 12 contributing medical centers for joint association analysis of 83,717 human participants. In this report, we describe the imputation of eMERGE results and methods to create the unified imputed merged set of genome‐wide variant genotype data. We imputed the data using the Michigan Imputation Server, which provides a missing single‐nucleotide variant genotype imputation service using the minimac3 imputation algorithm with the Haplotype Reference Consortium genotype reference set. We describe the quality control and filtering steps used in the generation of this data set and suggest generalizable quality thresholds for imputation and phenotype association studies. To test the merged imputed genotype set, we replicated a previously reported chromosome 6 HLA‐B herpes zoster (shingles) association and discovered a novel zoster‐associated loci in an epigenetic binding site near the terminus of chromosome 3 (3p29).

Associations of General and Central Adiposity With Incident Diabetes in Chinese Men and Women

OBJECTIVE

We assess associations of general and central adiposity in middle age and of young adulthood adiposity with incident diabetes in adult Chinese and estimate the associated population burden of diabetes.

RESEARCH DESIGN AND METHODS

The prospective China Kadoorie Biobank enrolled 512,891 adults 30-79 years of age from 10 localities across China during 2004-2008. During 9.2 years of follow-up, 13,416 cases of diabetes were recorded among 482,589 participants without diabetes at baseline. Cox regression yielded adjusted hazard ratios (HRs) for incident diabetes associated with measures of general (e.g., BMI and BMI at 25 years) and central (e.g., waist circumference [WC]) adiposity.

RESULTS

The mean (SD) BMI was 23.6 kg/m² (3.4 kg/m²), and 3.8% had a BMI ≥30 kg/m². Throughout the range examined (19-32 kg/m²), BMI showed a positive log-linear relationship with diabetes, with adjusted HRs per SD higher usual BMI greater in men (1.98; 95% CI 1.93-2.04) than in women (1.77; 1.73-1.81) (P for heterogeneity <0.001). For WC, HRs per SD were 2.13 (95% CI 2.07-2.19) in men and 1.91 (1.87-1.95) in women (P for heterogeneity <0.001). Mutual adjustment attenuated these associations, especially those of BMI. BMI at age 25 years was weakly positively associated with diabetes (men HR 1.09 [95% CI 1.05-1.12]; women 1.04 [1.02-1.07] per SD), which was reversed after adjustment for baseline BMI. In China, the increase in adiposity accounted for ∼50% of the increase in diabetes burden since 1980.

CONCLUSIONS

Among relatively lean Chinese adults, higher adiposity-general and central-was strongly positively associated with the risk of incident diabetes. The predicted continuing increase in adiposity in China foreshadows escalating rates of diabetes.

Association of adiposity with pulmonary function in older Chinese: Guangzhou Biobank Cohort Study

OBJECTIVE

We examined the association between different adiposity indices and pulmonary function in Chinese adults in the Guangzhou Biobank Cohort Study (GBCS).

METHODS

Participants with body mass index (BMI) < 18.5 (underweight) were excluded. Adiposity indices including BMI, waist circumference (WC), waist hip ratio, waist height ratio and body fat percentage were measured. Lung function was assessed by spirometry using a turbine flowmeter. We analyzed percent predicted for forced expiratory volume in 1 s (FEV₁%), forced vital capacity (FVC %) and restrictive respiratory defect (FEV₁/FVC ratio > low limits of normal and FVC % <0.80).

RESULTS

Of 16186 participants (mean age 61.4 ± 7.2 years; 74.0% women), 116 (0.7%) had only general obesity (BMI ≥28 kg/m²), 4079 (25.2%) had only central obesity (WC: ≥90 cm in men, ≥80 cm in women) and 1591 (9.8%) had both central obesity and general obesity. Comparing to those with neither central nor general obesity, those with only central adiposity and with both central and general obesity had lower pulmonary function (adjusted β range from -2.85 to -6.02 for FEV₁% and FVC%, adjusted OR range from 1.14 to 1.70, all P < 0.05). But those with only general obesity had better but non-significant pulmonary function. (Crude β range from 1.46 to 2.92 for FEV₁% and FVC%, crude OR range from 0.68 to 0.93, all P > 0.05). Both FEV₁% and FVC% decreased per standard deviation increase in obesity indices (adjusted β from -0.46 to -3.17, all P < 0.002). A positive association of central or general obesity with restrictive respiratory defect was observed (adjusted odds ratio (AOR) from 1.50 to 2.04, all P < 0.002). Further adjustment for WC reversed the inverse association between BMI and pulmonary function (adjusted β from 1.93 to 6.22, all P < 0.001) and restrictive respiratory defect (adjusted AOR from 0.72 to 0.80, all P < 0.001).

CONCLUSION

Central adiposity and its indices, but not general adiposity and BMI, were independently associated with lower pulmonary function and higher risk of restrictive respiratory defect in older Chinese.