Urban-rural-specific trend in prevalence of general and central obesity, and association with hypertension in Chinese adults, aged 18–65 years

Abstract

Background China has the largest obese population in the world, and the prevalence of central obesity is increasing dramatically in China. Moreover, the rapid economic growth of China in recent decades has led to rapid urbanization in rural China. However, studies comparing the prevalence trends of different types of obesity and the association of obesity with hypertension between urban and rural areas in China are very scarce, and most studies have focused only on the difference in the prevalence of overweight and general obesity or hypertension among rural and urban populations. Therefore, the focus of this study was to examine the shifts in the overall distribution of the prevalence of different types of obesity and to estimate the risk of hypertension in different types of obesity among urban and rural adults aged 18–65 years. Methods Seven iterations of the China Health and Nutrition Survey (CHNS), conducted in 1993, 1997, 2000, 2004, 2006, 2009 and 2011, were used in this study. A total of 53,636 participants aged 18–65 years were included. Obesity was classified into three types based on body mass index (BMI) and waist circumference (WC). A log-binomial model was constructed to estimate the prevalence ratio (PR) of hypertension with three types of obesity. Results The age-standardized prevalence of central obesity only, general obesity only, and both central and general obesity increased from 15.8, 0.2 and 2.9% in 1993 to 30.3, 0.9 and 10.3% in 2011, respectively. The prevalence of central obesity only (urban vs. rural: 20.8% vs. 13.4% in 1993, 29.6% vs. 30.6% in 2011) and both central and general obesity (urban vs. rural: 3.5% vs. 2.5% in 1993, 10.0% vs. 10.6% in 2011) in rural adults exceeded that in urban adults in 2011. Participants with both central and general obesity had the highest risk for incident hypertension compared with those with normal body measurements (adjusted PR, urban: 2.30 (95% CI , 2.01–2.63), rural: 2.50 (95% CI , 2.25–2.77)). Conclusions Both WC and BMI should be considered measures of obesity and targeted in hypertension prevention. More attention should be paid to the incidence of central obesity in adults in rural China.

Different anthropometric indicators of central obesity can predict hypertension in older adults

“…As previously explained, studies conducted with populations of different age groups have supported the hypothesis of a close association between central obesity and the development of CVD, especially the hypertension (17,19,20). The mechanisms involved are complex and still poorly understood, generating hypotheses such as the capacity of the visceral adipose tissue to secrete Renin-Angiotensin-Aldosterone System (RAAS) elements, and adipokines able to regulate blood pressure (11,21,22).…”

Joint Effects of Body Mass Index and Waist Circumference on the Incidence of Hypertension in a Community-Based Chinese Population

“…Women who were 18-39 years old and who had a nonobese BMI but a high WC showed a 1.96-fold higher risk of hypertension, and women who were 40-59 years old and had a high BMI but a nonobese WC also had a higher risk of hypertension, compared with women with nonobese BMI and WC [40]. Another study showed that the risk of hypertension among the three types of obesity in adults in urban areas was both central and general obesity > general obesity only > central obesity only, and in adults in rural areas it was both central and general obesity > central obesity only > general obesity only [8]. Thus, each index has both advantages and disadvantages.…”

“…A cohort study of US adults found that high WC may not be related to BMI, which suggests that a combination of BMI and WC may be a better predictor of obesity-related disease than BMI or WC alone [6]. Subsequently, other studies have shown that approximately two-thirds of obesity cases would go undiagnosed if WC were not measured in China [7,8]. These findings emphasize the importance of using both BMI and WC to define categories of obesity that predict obesity-related hypertension.…”

Investigation of the association between obesity and insulin-induced gene 1 polymorphism at 7q36.3 region in Uygur population in Xinjiang, China

“…Our results show that rs2721 and rs9719268 are significantly associated with obesity susceptibility. Obesity is a common heritable trait and a major risk factor for the development of hypertension, diabetes, coronary heart disease and stroke [20][21][22][23][24][25]. Long-term trends of overweight indicate a strong impact of lifestyle on the risk of obesity, despite this, many studies that aim to evaluate family heredity have proven the influence of genetic factors on BMI [13,26].…”