Risk factors
Education was classified using International Standard
Classification of Education as (a) no formal schooling and (b)
attended school.12 Work status was categorized as unemployed
and employed (economically productive occupations in both
formal and informal sectors) as per the Government of India
Census 2001.13 Socioeconomic status (SES) was measured
as per capita income in Indian rupees (Rs) and graded as per
Prasad’s classification; modifying for Consumer Price Index
for 2006–2007, the social classification value was determined
as 486.14 Per capita income per month was grouped as Rs
≥ 2400 (Class 1) and Rs < 2400 (other classes). Family history
of T2DM in first- or second-degree relatives was obtained.
Physical activity was measured using the International Physical
Activity Questionnaire15 (short version). Total metabolic
equivalents/week (MET/wk) were calculated and individuals
grouped as physically inactive (< 600 MET/wk) and physically
active (≥ 600MET/wk). Smoking was defined as the current
use of any tobacco product (cigarettes, bidis, chewing tobacco
or snuff) on a regular basis for at least the previous six
months.16 Individuals who said they had not smoked during
the survey period were classified as non-smokers. Alcohol use
was defined as the consumption of any type of alcohol in the
past 12 months.16 Body mass index (BMI) was calculated and
classified as per BMI classification for Indians (< 23 kg/m2 as
normal and ≥ 23 kg/m2 as overweight and obese).