This study assessed the prevalence of Metabolic Syndrome and its associated factors among females of reproductive age in Wakiso district, Uganda. The prevalence of MetS among the women of reproductive age in central Uganda was high at 17.8% (95% CI 13.2–23.6). Among the individual components of MetS, raised waist circumference had the highest prevalence at 63% (439/697), followed by reduced HDL cholesterol at 47.3% (330/697) and raised blood pressure at 25% (174/697). Raised triglycerides was at 14.2% (99/697) while raised fasting blood sugar had the lowest prevalence at 7.2% (50/697). The risk factors significantly associated with MetS were overweight and obesity, while breastfeeding of the most recent baby was a protective factor against Metabolic Syndrome.
Research on Metabolic Syndrome among women of reproductive age is limited. A study conducted among pregnant women receiving antenatal care in a hospital in Cameroon, reported a prevalence rate of 17.8%, (34) which is similar to our findings. However, while the Cameroon study focused exclusively on pregnant women, our research excluded this group from among the women of reproductive age considered.
The high prevalence of Metabolic Syndrome (MetS) found in our study is consistent with findings from previous research conducted in rural southwestern Uganda, which reported a MetS prevalence of 19.1% (35). A study in Ethiopia found a similar prevalence rate of 17.3% (36). However, while these prevalence rates are comparable to our findings, the study populations were different. Our research specifically targeted women of reproductive age, in contrast to the other studies that investigated MetS in the general adult population. The finding that MetS prevalence is equally high among women of reproductive age as it is in the general population underscores the significant concern for this population of women of reproductive age. This suggests a need to develop tailored interventions to mitigate the adverse impacts of MetS among women of reproductive age.
The three most common components of MetS found among the participants in this study were raised waist circumference 63% (439/697), reduced HDL cholesterol 47.3% (330/697) and high blood pressure 25% (174/697). These results align with the findings from research conducted in West Africa (37) and Uganda (35). The finding of a high prevalence of these three MetS components across diverse regions and populations highlights the regional importance of these MetS components and underscores the need for comprehensive public health interventions to address these common risk factors.
The most common component of MetS reported by our study was raised waist circumference at a prevalence of 63%. However, a recent study by Ben-Yacov L, et al. 2020 in rural south western Uganda, found the prevalence of raised waist circumference to be lower at 24.6% (35). This result may be explained by the fact that the cut off points for raised waist circumference used in Ben-Yacov L, et al. 2020’s study was higher (≥ 88 cm), compared to the lower cut off used in our study of ≥ 80 cm. Therefore, our study could have identified more women with raised waist circumference because of the lower cut off point and hence the observed higher prevalence of raised waist circumference. The finding of a high prevalence of raised waist circumference among women with Metabolic Syndrome presents an opportunity to explore the feasibility of using waist circumference as a rapid screening tool for identifying women who may be at high risk for Metabolic Syndrome in this setting (38).
Our study revealed a high prevalence of reduced HDL cholesterol at 47.3% (n = 330). Another Ugandan study also found a similarly high prevalence of reduced HDL cholesterol of 52.5% (35). The fact that reduced HDL cholesterol was the second commonest contributor to MetS is not surprising because various studies including in West Africa (34, 37) have found that reduced HDL cholesterol is quite prevalent in African populations and that there has been a trend towards decreasing levels of HDL cholesterol in Africans, orchestrated by urbanization and dietary changes. HDL cholesterol acts as an antithrombotic, anti-inflammatory and anti-oxidant, and subsequently, a low level of HDL cholesterol is considered a cardiovascular risk factor (37). These findings emphasize the importance of public health initiatives for mitigating this risk factor and promoting cardiovascular health in the African setting at large. Further exploration into the specific drivers of reduced HDL cholesterol in our region is warranted to inform targeted interventions.
In this study, the prevalence of high blood pressure was 25% (21.1% − 29.3%). Our finding is consistent with that of another Ugandan study which reported a prevalence of hypertension among females at 25.2%. (39). Furthermore, a study conducted in rural eastern Uganda reported a prevalence of 20.4% for hypertension among females (40). However, in contrast to the two previous studies that used a cut-off of ≥ 140/90 mmHg to define high blood pressure, our study employed a lower cut-off point of ≥ 130/85 mmHg. Despite the differences in cut off points, the prevalence of high blood pressure in the study population is high, and reflects a major public health concern that needs to be addressed through early detection and prompt management at the local, national and global levels. The WHO estimates that approximately 33% of the global population suffers from hypertension (41).
The prevalence of raised triglycerides established by our study was 14.2% (n = 99). Of those, 10.3% had Metabolic Syndrome, emphasizing the clinical relevance of this lipid abnormality. This prevalence of raised triglycerides among females of reproductive age is almost similar to the 16.9% prevalence of raised triglycerides obtained in a study conducted in the general population in rural Uganda (35). This is in stark contrast with the high prevalence of reduced HDL cholesterol of 47.3% observed in this study. Studies among African populations elsewhere also indicate a similar trend that triglyceride levels are unexpectedly low or even normal in comparison to the prevalence of reduced HDL cholesterol, in spite of the presence of insulin resistance, Type 2 Diabetes Mellitus (T2DM) and Cardiovascular Disease (CVD). This phenomenon has been described as the ‘triglyceride paradox’, because triglycerides levels are expected to be high in tandem with reduced HDL cholesterol levels. However, a reverse association is observed in Africans (42). It is important to note that this paradox is not exclusive to Uganda; it is also observed in other African populations. Therefore, understanding the mechanism behind this unique lipid profile in African populations is of crucial importance for cardiovascular health research and may have implications for development of cardiovascular risk assessment and management strategies.
Our study found a high prevalence of fasting blood sugar of 7.2% (3.5% − 10.6%) (50/697) compared to the Uganda 2014 NCD risk factor baseline survey, in which the fasting blood sugar among females was 1.0% (0.5% − 1.5%) (26). It is worth noting that the cut-off for fasting blood sugar in the Uganda 2014 NCD survey was based on a capillary whole blood value of ≥ 7.0 mmol/l or 126 mg/dl, whereas in our study, the cut-off was set at ≥ 5.6 mmol/l or 100 mg/dl as per the Joint Interim Statement criterion (1). This difference in cut-off values may explain the higher prevalence of high fasting blood sugar observed in our study compared to the 2014 NCD survey, as the use of a lower cut-off point in our study could have resulted in more cases being identified. Nevertheless, a study conducted in Iganga-Mayuge districts, rural eastern Uganda, which employed a similar cut-off point as ours, reported a significantly higher prevalence of raised fasting blood sugar among females, at 20.2% (43).
Risk factors of Metabolic Syndrome
There was a higher prevalence of MetS among rural (28.5%) compared to urban residents (15.5%). This was an unexpected finding from our study. Studies have shown that the prevalence of MetS is higher in urban than rural residents (44, 45), due to urbanization, adoption of unhealthy lifestyles (45) and sedentariness. It is worth noting that our study used the demarcation of rural and urban areas defined by the Uganda Bureau of Statistics (UBOS). However, some enumeration areas that were classified as rural according to UBOS may have now transitioned to peri-urban status but are still classified as rural. This might have led to misclassification of urban clusters as rural, and may have contributed to the observed higher prevalence of Metabolic Syndrome among the rural residents in our study. Indeed, upon further review of our data set, it was found that out of the 5 clusters initially classified as rural, only 2 would be considered truly rural. Generally, Wakiso, along with Mukono district, is experiencing rapid urbanization as large portions of the district are transitioning to peri-urban areas, surrounding the Ugandan capital city Kampala. Wakiso district was selected because of its close proximity to the Ugandan capital, Kampala. This proximity increases the likelihood of a spillover effect of various factors, including lifestyle and environmental factors that are prevalent in the capital city and significantly contribute to the prevalence of non-communicable diseases. It is also undergoing rapid urbanization (39), and thus risk factors for NCDs like obesity (46) and hypertension (47) are prevalent.
There was a strong association between Metabolic Syndrome and overweight and obesity. Women who were overweight (BMI of 25.0-29.9) or obese (BMI of ≥ 30) were more likely to have Metabolic Syndrome (APR:3.96, 95% CI 1.98–7.90, p = < 0.001) or (APR: 6.11, 95% CI 3.22–11.64, p = < 0.001) respectively (Table 2). This is in keeping with previous studies, including a systematic review and meta-analysis from Ethiopia which also found an association between overweight and obesity and Metabolic Syndrome(48). Overweight and obesity are modifiable risk factors that can potentially be managed through lifestyle and behavioral interventions that focus on adopting healthy dietary habits and engaging in regular physical activities. Public health decision makers at district level and Ministry of Health should consider implementing and promoting programs that encourage healthy weight management, especially among women of reproductive age. These programs could focus on lifestyle and behavioral interventions, such as promoting healthy dietary habits and regular physical activity. These initiatives may have the potential to decrease the likelihood of Metabolic Syndrome and its associated health complications.
We found that breastfeeding was significantly associated with Metabolic Syndrome (APR:0.62, 95% CI 0.40–0.95 p = 0.028). This finding underscores the notion that a woman's reproductive health may exert a significant influence on her metabolic well-being. Indeed, various studies report an inverse association between duration of breastfeeding and the occurrence of Metabolic Syndrome (49–51). Some studies have argued that lactation may confer metabolic efficiency which may persist after the lactation period through improved insulin sensitivity, reduced visceral adiposity (49) and glycemic control (52). Other researchers argue that the favorable metabolic health could be linked to possible healthier lifestyles among women who choose to lactate (50). This finding suggests that breastfeeding among women has a positive impact on their metabolic health and should be promoted in women of reproductive age.
Strength and limitations
The main strength of this study is that it is the first study to determine the prevalence of Metabolic Syndrome among women of reproductive age in central Uganda. The study also employed a relatively large sample size of 697 participants.
This study, however, had some limitations. Metabolic Syndrome has several definitions depending on the criteria employed to diagnose the syndrome. This creates challenges in comparing study findings. This study employed the definition included in the Joint Interim Statement for diagnosis of MetS. The findings can be comparable with those of studies that have employed similar criteria to diagnose MetS. This study used a cross-sectional design and so it cannot infer causality.