Explaining non-communicable disease-related behavior in Nairobi City County, Kenya, in the context of family and poverty: Study design, methods, and population characteristics (Preprint)

BACKGROUND The prevalence of non-communicable diseases (NCDs) is increasing in the lower middle-income countries as these countries transition to unhealthy lifestyles which are mostly predominant in urban areas. OBJECTIVE The purpose of this paper is to describe the protocol; design, methods, and study population characteristics of a study explaining non-communicable disease-related behavior in Nairobi City County, Kenya, in the context of family and poverty. METHODS A cross-sectional study was conducted among 149 randomly selected pairs of 9-14 years old pre-adolescents and their guardians living in low- (Kayole) and middle-income (Langata) Sub-counties in Nairobi City County. This multidisciplinary study was conducted in two parts; the quantitative part involved the collection of dietary intake through a validated 12-food group (consisting of 174 foods) 7-day Food Frequency Questionnaire (FFQ) (for the pre-adolescents and their guardians) and two 24-hour recalls conducted on non-consecutive days (weekday and weekend) for the pre-adolescents. A photographic Food Atlas for Kenya Pre-adolescents specifically developed for this study and pilot tested for feasibility was used to estimate food portions. The sociodemographic characteristics were collected using a validated questionnaire. Weight, height, mid-upper arm circumference (MUAC), and waist circumference were measured using standard approved protocols. Physical activity was assessed objectively using waist-worn accelerometers for 24 hours over 8 days and self-reports using a validated questionnaire. Data were collected digitally using Android mobile devices and uploaded to the Open Data Kit (ODK) platform and stored on an online server. Data for the qualitative part of the study was collected through Key Informant Interviews (KIIs) and Focus Group Discussions (FGDs) on cultural and social beliefs related to obesity and physical activity. The data was to allow for triangulation with the quantitative data. The qualitative data were audio-recorded, transcribed, and imported to MAXQDA for analysis. Socioeconomic characteristics of the residential sites were accessed using the Wealth Index similar to the Demographic and Health Surveys (DHS) created using Principal Component Analysis. RESULTS A total of 149 households translating into a response rate of 93% participated in the study; 72 from Kayole and 77 from Langata. The majority of the participants residing in Kayole belonged to the lower income and education groups whereas participants residing in Langata belonged to the higher income and education groups. In Kayole, none of the participants belonged to the highest Wealth Index (highest fifth) whereas in Langata none of the participants belonged to the lowest Wealth Index (lowest fifth). CONCLUSIONS The findings of this research will provide novel and important new data on determinants of NCD-related lifestyles and risk factors in urban populations useful for setting priorities for NCD policy or programmes and further research on identified lifestyle changes in Kenya and other similar countries.