Association Between Body Mass index and Prevalence of Multimorbidity in Low-and Middle-income Countries: A Cross-Sectional Study.

Background: Chronic diseases are increasingly becoming a health burden in terms of both morbidity and mortality in low and middle-income countries (LMICs). The role of body mass index (BMI) especially overweight and obesity in the prevalence of multimorbidity, the occurrence of two or more chronic conditions, is understudied in LMICs where two thirds of the world's obese individuals reside. We estimated the association between BMI and prevalence of chronic non communicable disease multimorbidity in six LMICs.

Methods: Cross-sectional data of total of 40,166 participants from China (n=13,970), India (10,915), Mexico (2,4 26), Russia (3,892), South Africa (4,000) and Ghana (4,971), aged 18 years and above included in the WHO Study on Global Ageing and adult health (SAGE), 2007-2010 were analyzed. Multimorbidity was measured as the simultaneous presence of two or more of the nine chronic conditions including angina pectoris, arthritis, asthma, chronic lung disease, diabetes mellitus, hypertension, stroke, depression, and vision impairment. Multivariable logistic regression models were fitted to test for associations between overweight/obesity and prevalence of non communicable multimorbidity after adjusting for age, sex, rural/urban residence, education, marital status, occupation, household wealth, tobacco smoking, alcohol drinking, fruits and vegetable intake and health insurance status. Data were analyzed country wise as well as pooled together to give overall LMIC estimates.

Results: The mean BMI was 24.4 [±7.3SD] in the pooled countries, being as low as 20.8 [±8.0 SD] in India to 23.4 [±6.3 SD] in Ghana, 23.9 [±4.9 SD] in China, 28.4 [±5.4 SD] in Mexico, 28.6 [±6.3 SD] in Russia, to as high as 30.5 [±12.0 SD] in South Africa. The prevalence of overweight was 13% and obesity was 24% in the pooled sample. The prevalence of non communicable disease multimorbidity was 23% in the pooled sample of six countries-the highest being in Russia (50%), followed by Mexico (27%), India (24%), Ghana (23%), South Africa (32%) and China (22%). The prevalence of multimorbidity was 37% among obese population and 27% among overweight population in the pooled sample-highest prevalence was in Russia (59% among obese; 45% among overweight) and lowest in Ghana (28% among obese; 23% among overweight). Being obese (OR:5.78;95%CI:3.55-9.40;p<0.0001) was associated with significantly higher likelihood of having multimorbidity as compared to normal weight category in the pooled sample. The likelihood of multimorbidity among obese were almost ten times higher in Russia (OR:9.90;95%CI:3.90-25.17;p=<0.0001), seven times higher in China (OR:7.06;95%CI:2.47-20.21;p=0.003), six times higher in Ghana (OR:5.61;95%CI:1.21-26.02;p= 0.007) and five times higher in South Africa (OR:4.66;95%CI:2.16-10.08;p=0.005). Non-significant but positive association were also observed in case of India and Mexico. The likelihood of multimorbidity was more than two times higher among overweight population in India (OR:2.33;95%CI:1.35-4.02;p=0.003) and pooled countries (OR:1.47;95%CI:1.05-2.07;p=0.004) while non-significant but positive association were also observed in case of China, Russia, and Ghana.

Conclusions: The prevalence of non communicable disease multimorbidity in the LMICs is high, one and half times higher in obese than in normal weight individual. Obesity was independently associated with the occurrence of multimorbidity in the six LMICs. These findings may be vital for public health surveillance, prevention and management strategies for non communicable disease multimorbidity in the LMICs.