Physical activity and the risk for gestational diabetes mellitus amongst pregnant women living in Soweto: a study protocol

Background: Over the past decade the prevalence of gestational diabetes mellitus (GDM) has increased rapidly in both developed and developing countries and has become a growing health concern worldwide. A recent systematic review highlighted the paucity of data available on the prevalence and potential burden of GDM in Africa, which was emphasised by the fact that only 11 % of African countries were represented in the review. In South Africa, the prevalence of GDM remains unknown, although one would estimate it to be high due to urbanisation and the growing obesity epidemic. In addition, the association between physical activity (PA), sedentary behaviour (SB) and GDM is not well understood in this population. The aim of the proposed research is to determine whether there is an association between physical activity, sedentary behaviour and risk for GDM in pregnant black women living in urban Soweto in South Africa. Methods/Design: This prospective cohort study of 80 participants will include pregnant women from Soweto enrolled into the Soweto First 1000 Days Study (S1000) at the MRC/Wits Departmental Pathways for Health Research Unit (DPHRU) based at the Chris Hani Baragwanath Academic Hospital in Soweto, South Africa. Women will be enrolled into the S1000 Study at <14 weeks gestation, and baseline demographic and anthropometric measures will be taken at 14-18 weeks gestation (visit 1). In addition, participants will complete the Global Physical Activity Questionnaire (GPAQ) to measure self-reported physical activity and will be given an ActiGraph accelerometer to wear for seven days to measure habitual physical activity at 14-18 weeks gestation (visit 1), and at 28-33 weeks gestation (visit 3). At visit 2 (24-28 weeks gestation) an oral glucose tolerance test (OGTT) will be conducted. Discussion: Physical activity during pregnancy has been associated with minimum risk to a pregnancy and may play a role in improving glucose metabolism and therefore decreasing risk for GDM. This is particularly pertinent to assess amongst black South African women who are a potentially high risk population due to the high prevalence of obesity and type 2 diabetes (T2D). The findings of the study will assist in developing targeted interventions as well as feasible healthcare strategies.