ICMR-INDIAB

The ICMR-INDIAB study is a cross-sectional, population-based survey of adults aged 20 years and older. Briefly, the study sampled urban and rural residents in 31 states and union territories of India using a stratified multistage sampling design. In order to obtain a truly representative sample of the population, we used three-level stratification based on geography, population size, and socioeconomic status of each state. The primary sampling units were villages in rural areas and census enumeration blocks in urban areas. Using a systematic sampling method, 24 and 56 households were selected from urban and rural areas, respectively. Door-to-door

assessment was done and from each household, one individual was selected based on the WHO Kish method, to avoid selection bias with respect to sex and age. The study was conducted in a phased manner between November, 2008, and December, 2020. In phase 1, four regions representing the south (Tamil Nadu), north (Chandigarh), east (Jharkhand), and west (Maharashtra) of the country were studied from Oct 18, 2008, to April 16, 2010. The remaining states were surveyed as follows: phase 2 consisted of undivided Andhra Pradesh (subsequently divided into Andhra Pradesh and Telangana), Bihar, Gujarat, Karnataka, and Punjab (survey period, Sept 24, 2012, to July 26, 2013), the north east phase included Assam, Arunachal Pradesh, Manipur, Meghalaya, Mizoram, Nagaland, Sikkim, and Tripura (survey period, Dec 5, 2011, to Nov 14, 2017), phase 3 included Delhi, Madhya Pradesh, Rajasthan, and Uttar Pradesh (survey period, Aug 24, 2017, to March 8, 2018), phase 4 included Kerala, Goa, Puducherry, Haryana, and Chhattisgarh (survey period, Dec 10, 2018, to July 10, 2019), and phase 5 included Himachal Pradesh, Uttarakhand, Odisha, and West Bengal (survey period,

Sept 1, 2019 to Dec 31, 2020).