Incidence, prevalence and risk factors for obesity among urban, adult Sri Lankans: a 7-year community cohort follow-up 
Niriella MA1, De Silva ST1, Kasturiratne A1, Ranasinghe RMAG1, De Silva AP1, Pathmeswaran A1, Wickramasinghe AR1, Kato N2, de Silva HJ1
1Faculty of Medicine, University of Kelaniya, 2National Center for Global Health and Medicine, Tokyo, Japan.

Background
Obesity is a major risk factor for cardiovascular disease, diabetes, osteoarthritis and some types of malignancies. The risk of these non-communicable diseases increases with increased body-mass index (BMI). 13% of the world’s population aged 18 years and over were obese, and 39% were overweight in 2014 (WHO estimates). The worldwide prevalence of obesity more than doubled between 1980 and 2014. Previous studies have estimated prevalence rates of 25.2%, 9.2% and 26.2% for overweight, general obesity (GO) and central obesity (CO) respectively, among Sri Lankan adults (Katulanda et al, 2010). However, data on incidence and risk factors for GO and CO from the South Asian region is limited.
Aims
We investigated the incidence, prevalence and demographic and life style risk factors for GO and CO among urban, adult Sri Lankans in a prospective, community cohort follow-up study.
Method
We included urban, adult, Sri Lankans (selected by age-stratified random sampling) from Ragama Medical Officer of Health area, Gampaha District, Sri Lanka. The initial screening was done in 2007 (aged 35-64 years) and re-evaluation took place in 2014 (aged 42-71 years). On both occasions structured interview, anthropometry, liver ultrasound, biochemical and serological tests were performed. Total body fat (TBF) and visceral fat percentage (VFP) were assessed by impedance in 2014. GO was defined as BMI >25kg/m2. CO was defined as waist circumference (WC) >90cm for males and >80cm for females. Multinomial logistic regression was fitted to assess associations.
Results
In 2007 (n=2967), 614 (20.7%) were overweight [51.9% women], 1161 (39.1%) had GO [65.9% women] and 1584 (53.4%) had CO [71% women]. Female gender (p<0.001), raised triglycerides (p<0.001), low HDL (p<0.001), diabetes (p<0.001), hypertension (p<0.001), non-alcoholic fatty liver disease (NAFLD) (p<0.001), and low household income (p<0.001) were significantly associated with prevalent GO and CO respectively. Additionally, increased age (p=0.05), low-educational level (p<0.001) and unhealthy eating (p<0.001) were associated with prevalent CO. Inadequate physical activity was not associated with either. 
2137 (72%) attended follow-up in 2014. Of those who were initially non-obese who attended follow-up, 189/1270 (14.9%) [64% women] had developed GO (annual incidence 2.13%) and 206/947 (21.9%) [56.3% women] had developed CO (annual incidence 3.12%) after 7 years. TBF and VFP significantly correlated with incident GO and CO (p<0.001).  Female gender (OR 1.78, p<0.001; OR  2.81, p<0.001) and NAFLD (OR 2.93, p<0.001; OR 2.27, p<0.001) independently predicted incident GO and CO, respectively. 
Discussion 
Prevalence of GO and CO in this cohort was 39.1% and 53.4%, and incidence was 2.13% and 3.12%, respectively. Female gender and NAFLD independently predicted the development of future incident GO and CO.