Sampling scheme and participation in the study. Figure 1 illustrates the sampling of participants in the study. The target group was defined as individuals above the age of 17 living in the neighbourhoods. For the current study, a stratified random sample of 7,934 households was selected. Of the 7,934 households, 641 were excluded from the study, as the residents had moved, died, or were otherwise unavailable. One person from each of the remaining households was selected, and quota sampling with respect to gender and age was used as the sampling procedure. Of the net sample of 7,293 individuals, 1,464 refused to participate, 885 were not at home, and 373 did not participate for other reasons, resulting in an average response rate of 62.7%.