Morbidity compression or expansion? A temporal analysis of the age at onset of non-communicable diseases in India.

While there is evidence of morbidity compression in many countries, temporal patterns of non-communicable diseases (NCDs) in developing countries, such as India, are less clear. Age at onset of disease offers insights to understanding epidemiologic trends and is a key input for public health programs. Changes in age at onset and duration of major NCDs were estimated for 2004 (n = 38,044) and 2018 (n = 43,239) using health surveys from the India National Sample Survey (NSS). Survival regression models were used to compare trends by sociodemographic characteristics. Comparing 2004 to 2018, there were reductions in age at onset and increases in duration for overall and cause-specific NCDs. Median age at onset decreased for NCDs overall (57 to 53 years) and for diabetes, hypertension, heart disease, asthma, mental diseases, eye disease, and bone disease in the range of 2-7 years and increased for cancer, neurological disorders, some genitourinary disorders, and injuries/accidents in the range of 2-14 years. Hazards of NCDs were higher among females for cancers (HR 1.51, 95% CI 1.19-1.90) and neurological disorders (HR 1.18, 95% CI 1.06-1.32) but lower for heart diseases (HR 0.88, 95% CI 0.79-0.97) and injuries/accidents (HR 0.87, 95% CI 0.77-0.99). Hazards were greater among those with lower educational attainment at younger ages and higher educational attainment later in life. Unlike many countries, chronic disease morbidity may be expanding in India for many chronic diseases, indicating excess strain on the health system. Public health programs should focus on early diagnosis and prevention of NCDs.