Table 5 Challenges in the implementation of the study and methods used to overcome them

Mapping and listing of households

Reference data Delhi and Chennai: 2001 census. Karachi: 1998 census.

Complete listing of all the households in all randomly selected CEBs was done by field workers and structural maps of the areas were developed manually.

Lot of changes in structure and population had taken place by 2010

Training of trainers (ToT) and site managers for uniform implementation of the study

Challenges with regards to organising the ToT in either India or Pakistan due to visa issues for trainers and participants.

The ToT was organised in Kathmandu, Nepal with assistance from the Nepal Public Health Foundation.

Participant recruitment and interviews

Poor response from upper socioeconomic status localities and gated communities

Resident Welfare Association, Societies and Unions of the localities were approached for cooperation.

Recruiting and interviewing male participants - who could not be contacted on working days

Interviews were scheduled on weekends, early mornings and late evenings, and more field workers were recruited to conduct these weekend surveys.

Frequent electricity breakdowns in Karachi in the evenings.

Emergency lights were arranged for interviewing the participants in the evenings.

The socio-political climate in Karachi posed challenges to the safety of interviewers and in completion of surveys.

Field work was scheduled accordingly to target safe areas as per the socio-political situation of the city on a day-to-day basis.

Blood sample collection

Fear of providing blood samples among the participants of lower socio economic status

Team leader and supervisor contacted and counselled the participants.

Not coming fasting to the blood collection camps – some participants consumed tea or juices early in the morning.

The blood samples for these participants were not collected in the camp on that day, but were collected on another day from their homes ensuring that the participant was in fasting state. The samples were transported to the laboratory in appropriate cold chain.

Blood samples could not be collected during the month of Ramadan (Islamic fasting month) in Karachi.

During the month of Ramadan, non-Muslim participants (mainly from the Christian communities) were recruited.

Difficulty in conducting blood collection camps during extreme (cold and hot) weather conditions.

As far as possible camps were avoided on extreme cold and hot days in Delhi.

Anthropometry

The instrument purchased for the other two sites Tanita BC-418 was not available at Karachi and also could not be shipped in to the country.

A different model of Tanita was used in Karachi, BC-554, but the two models were compared by measuring the correlation of their parameters in 100 participants (described in the text).

Bio-impedance