Trends in cardiovascular disease risk factors by body mass index category among adults in England 2003-18: analysis of repeated cross-sectional national health surveys

Objective Favourable trends in cardiovascular disease (CVD) risk factors at the population level potentially mask differences within high- and low-risk groups. Data from annual, repeated cross-sectional surveys (Health Survey for England 2003-18) was used to examine trends in the prevalence of key CVD risk factors by body mass index (BMI) category among adults aged 16 years or older (n = 115,860). Methods Six risk factors were investigated: (i) current cigarette smoking; (ii) physical inactivity (< 30 minutes of moderate-to-vigorous physical activity per week); (iii) drinking above recommended daily alcohol limits; (iv) hypertension (measured blood pressure ≥140/90mmHg or use of medicine prescribed for high blood pressure); (v) total diabetes (reported diagnosed or elevated glycated haemoglobin); and (vi) raised total cholesterol (≥5mmol/L). Age-standardised risk factor prevalence was computed in each four-year time period (2003-06; 2007-10; 2011-14; 2015-18) in all adults and by BMI category (normal-weight; overweight; obesity). Change in risk factor prevalence on the absolute scale was computed as the difference between the first and last time-periods, expressed in percentage points (PP). Results Risk factor change varied by BMI category in a number of cases. Current smoking prevalence fell more sharply for normal-weight men (−8.1 PP; 95% CI: -10.3, -5.8) versus men with obesity (−3.8 PP; 95% CI: -6.2, -1.4). Hypertension remained at a stable level among normal-weight men but decreased among men with obesity (−4.1 PP; 95% CI: -7.1, -1.0). Total diabetes remained at a stable level among normal-weight adults, but increased among adults with obesity (men: 3.5 PP; 95% CI: 1.2, 5.7; women: 3.6 PP; 95% CI: 1.8, 5.4). Raised total cholesterol decreased in all BMI groups, but fell more sharply among women with obesity (−21 PP; 95% CI: -25, -17) versus their normal-weight counterparts (−16 PP; 95% CI: -18, -14). Conclusions Relative to adults with normal weight, greater reductions in hypertension and raised total cholesterol among adults with overweight and obesity reflect at least in part improvements in screening, treatment and control among those at highest cardiovascular risk. Higher levels of risk factor prevalence among adults with overweight and obesity, in parallel with rising diabetes, highlight the importance of national prevention efforts to combat the public health impact of excess adiposity.