Background: A worldwide increase in the prevalence of diabetes mellitus (DM) has been reported and an even further increase is expected as a result of lifestyle changes. The objectives of this study were to determine the prevalence of DM in the rural southern Free State and to investigate the contribution of risk factors such as age, physical activity, body mass index (BMI), waist-to-hip ratio and waist circumference to the development of impaired fasting glucose (IFG) or DM.

Methods: Fasting venous plasma glucose (FVPG) levels were obtained from a total of 552 participants from Springfontein (n = 195), Trompsburg (n = 162) and Philippolis (n = 180). Participants were between 25 and 64 years of age, with 28.1% male (mean age 47.3 years) and 71.9% female (mean age 46 years). Anthropometric status was determined using standardised techniques. Levels of physical activity were determined using a 24-hour recall of physical activity as well as frequency of performing certain activities. Relative risks (RR) as well as 95% confidence intervals (95% CI) were used to distinguish significant risk factors for having IFG or DM.

Results: In the study population the prevalence of DM was 7.6% (5.2% in men and 8.6% in women) and that of IFG was 6.3% (4.5% in men and 7.1% in women). The majority of nondiabetic (34%), IFG (55%) and DM (61%) participants were between the ages of 51 and 60 years. Age was found to be a statistically significant risk factor for having IFG or DM in participants older than 40 years of age (RR 2.3; 95% CI [1.22; 4.34]). Crude measurements (not age- and gender-adjusted) of waist circumference (RR 3.23; 95% CI [1.82; 5.74]), BMI (RR 2.32; 95% CI [1.43; 3.78]) and waist-to-hip ratio (RR 2.51; 95% CI [1.55; 4.07]) were statistically significant risk factors for having IFG or DM. Physical inactivity in men ≥ 40 years was also a statistically significant risk factor (RR 3.23; 95% CI [1.15; 9.05]) for having IFG or DM.

Conclusions: In this study, 37.5% of diabetics were newly discovered. A high waist circumference, BMI and waist-to-hip-ratio were associated with an increased risk for developing IFG or DM, with a high waist circumference being the most significant general risk factor. Physically inactive men (≤ 40 years) were also at a higher risk of having IFG or DM. Follow-up FVPG and glucose tolerance tests should be performed on participants in the IFG group. A need for intervention regarding the identification and treatment of DM in these rural areas has been identified.