Abstract
There is a need for a modified Global Physical Activity Questionnaire (GPAQ) to estimate physical activity levels more accurately in populations. We aimed to develop a modified GPAQ and examine its construct validity among adults in Kerala, India. We incorporated locality-specific, metabolic equivalent task (MET)-based activities into the original GPAQ and administered this modified GPAQ among randomly selected 451 individuals (age ≥ 20 years) residing in the Trivandrum district of Kerala. Construct validity of the modified GPAQ was assessed using generalized linear models by examining the association of total moderate-to-vigorous physical activity (MVPA) MET-minutes per week with clinical measures. The mean age of participants was 45.4 (SD: 14.1) years, and 52.6% were female. Increasing total MVPA MET-minutes per week was associated with decreasing weight (β = −0.011 kg, 95% CI: −0.020, −0.002), waist circumference (β = −0.013 cm, 95% CI: −0.023, −0.004), and systolic blood pressure (β = −0.009 mmHg, 95% CI: −0.015, −0.002), independent of age, sex, education, occupation, current smoking, current alcohol use, and fruit and vegetable intake. The validity coefficients and associations between total MVPA MET-minutes per week and theoretical constructs of physical activity agreed with those predicted, providing evidence of construct validity for the modified GPAQ.