Changes in waist circumference and risk of all-cause and CVD mortality: results from the European Prospective Investigation into Cancer in Norfolk (EPIC-Norfolk) cohort study

Background: Measures of abdominal adiposity are strongly associated with all-cause mortality and cardiovascular disease (CVD). However, data are limited and conflicting regarding the consequences of changes in body fat distribution. The main aims of this paper are to investigate the association between changes in waist circumference (WC) and all-cause and CVD mortality and to examine these changes in relation to concurrent changes in weight. Methods: The European Prospective Investigation into Cancer and Nutrition (EPIC-Norfolk) study recruited 25,639 participants between 1993 and 1997, aged 39-79, a number of whom also attended a second examination (1998-2000), and were followed up to 2016 for mortality. Participants were eligible for inclusion if they had WC, weight and height measurements at both time-points; those with a self-reported history of CVD or cancer, body mass index < 18.5 kg/m2 or missing data on covariates were excluded, leaving 12,337 participants for analyses. The median (IQR) follow-up time was 16.4 (15.7, 17.2) years. Hazard Ratios (HRs) for all-cause (2866 deaths) and CVD mortality (822 deaths), by categories of WC change, were determined using Cox proportional hazards analyses. Results: After multivariable adjustment, the HRs (95% CIs) for all-cause mortality for men and women with a WC gain (WCG) > 5 cm were 1.51 (1.29-1.75) and 1.25 (1.06-1.46) respectively. For CVD mortality in men and women with a WCG > 5 cm, the HRs were 1.84 (1.39-2.43) and 1.15 (0.85-1.55) respectively. In analyses of concurrent changes in WC and weight, the greatest risk (HRs) (95% CIs) in men occurred with weight loss and WCG: 1.80 (1.13-2.86) for all-cause and 2.22 (1.03-4.82) for CVD mortality. In women, the greatest risk for both all-cause (HR 1.50 (1.16-1.95)) and CVD mortality (HR 1.81 (1.15-2.85)) was observed in those with weight loss and maintenance of WC (WCM). Conclusions: Objectively measured WCG > 5 cm, was associated with subsequent higher total mortality risk and higher CVD mortality risk in men. Interventions focusing on preventing increase in central adiposity rather than lowering weight per se in later life may potentially have greater health benefits.