Data collection
Data collection comprised an interview and
physical examination conducted in a survey station
established close to the residential area of the study
participants. The questionnaire and examination weredone by specially trained study staff according to a
standardized protocol. The questionnaire included
broad ranging questions about demographic
characteristics, health-related behaviors and history
of illnesses. The physical examination comprised
measurement of body weight, height, blood pressure
and visual acuity using standardized anthropometric
techniques and equipment(10).
Definitions