Sub-national patterns and correlates of depression among adults aged 45 years and older: findings from wave 1 of the Longitudinal Ageing Study in India.

backgroundDepression is a major public health challenge linked with several poor health outcomes and disabilities among adults aged 45 years and older in India. We aimed to describe the prevalence of depression and its association with a variety of sociodemographic correlates and co-existing health conditions for this age group in India and its states.

methodsIn this prospective cohort study, data from wave 1 (baseline) of the Longitudinal Ageing Study in India were used to estimate the national and subnational state level age-standardised prevalence of depression-major depressive episodes-using the internationally validated Composite International Diagnostic Interview-Short Form (CIDI-SF) scale. Hierarchical mixed effect multivariate logistic regression models were used to study the sociodemographic correlates and co-existing health conditions of major depressive episodes among the nationally representative sample of 72 250 adults aged 45 years and older from 35 states or union territories (except the state of Sikkim). Associations between depression and self-rated health, co-morbid conditions, functional health, and life satisfaction measures were also examined.

findingsA total of 40 335 (58·3%) females and 29 407 (41·7%) males aged 45 to 116 years (median age 58 years) participated. The overall age-standardised prevalence of depression based on CIDI-SF scale was 5·7% (95% CI 5·5-5·8) compared with 0·5% (0·5-0·6) self-reported prevalence of depression among adults aged 45 years and older in India. Wide sub-national variations were seen in depression prevalence, ranging from 0·8% (95% CI 0·3-1·3) in Mizoram state to 12·9% (11·6-14·2) in Madhya Pradesh. Prevalence was higher in females (6·3% [95% CI 6·1-6·6] vs 4·3% [4·1-4·6]) for India, and this higher prevalence was more pronounced in some of the northern states. The risk of depression was higher in those residing in rural areas, widowed, with no or low education, and in the poorest quintile. Depression showed a strong positive association with poor self-rated health (OR 2·39 [95% CI 2·21-2·59]; p<0·0001), with one or more limitations in the activities of daily living (ADL; OR 1·60 [1·46-1·75]; p<0·0001), instrumental ADL limitations (OR 1·51 [1·40-1·64]; p<0·0001), and low cognitive judgment of life satisfaction (OR 1·94 [95% CI 1·78-2·10]; p<0·0001).

interpretationDespite the substantial burden, depression remains undiagnosed and strongly linked with poor health and wellbeing outcomes in adults aged 45 years and older in India. The ageing population of India and the subnational variations amplify the implications of this new evidence to address the substantial gaps in prevention and treatment of depression.

fundingLASI was funded by the Ministry of Health and Family Welfare, Government of India, the National Institute of Ageing, USA and the United Nations Population Fund, India.