Browsing by Author "Dalal, Shona"
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- ItemThe burden of hypertension in sub-Saharan Africa : a four-country cross sectional study(BioMed Central, 2015) Guwatudde, David; Nankya-Mutyoba, Joan; Kalyesubula, Robert; Laurence, Carien; Adebamowo, Clement; Ajayi, IkeOluwapo; Bajunirwe, Francis; Njelekela, Marina; Chiwanga, Faraja S.; Reid, Todd; Volmink, Jimmy; Adami, Hans-Olov; Holmes, Michelle D.; Dalal, ShonaENGLISH SUMMARY : Background: Hypertension, the leading single cause of morbidity and mortality worldwide, is a growing publichealth problem in sub-Saharan Africa (SSA). Few studies have estimated and compared the burden of hypertension across different SSA populations. We conducted a cross-sectional analysis of blood pressure data collected through a cohort study in four SSA countries, to estimate the prevalence of pre-hypertension, the prevalence of hypertension,and to identify the factors associated with hypertension. Methods: Participants were from five different population groups defined by occupation and degree of urbanization, including rural and peri-urban residents in Uganda, school teachers in South Africa and Tanzania, and nurses in Nigeria. We used a standardized questionnaire to collect data on demographic and behavioral characteristics, injuries, and history of diagnoses of chronic diseases and mental health. We also made physical measurements (weight, height and blood pressure), as well as biochemical measurements; which followed standardized protocols across the country sites. Modified Poison regression modelling was used to estimate prevalence ratios (PR) as measures of association between potential risk factors and hypertension. Results: The overall age-standardized prevalence of hypertension among the 1216 participants was 25.9 %. Prevalence was highest among nurses with an age-standardized prevalence (ASP) of 25.8 %, followed by school teachers (ASP = 23.2 %), peri-urban residents (ASP = 20.5 %) and lowest among rural residents (ASP = 8.7 %). Only 50.0 % of participants with hypertension were aware of their raised blood pressure. The overall age-standardized prevalence of pre-hypertension was 21.0 %. Factors found to be associated with hypertension were: population group, older age, higher body mass index, higher fasting plasma glucose level, lower level of education, and tobacco use. Conclusions: The prevalence of hypertension and pre-hypertension are high, and differ by population group defined by occupation and degree of urbanization. Only half of the populations with hypertension are aware of their hypertension, indicating a high burden of undiagnosed and un-controlled high blood pressure in these populations.
- ItemFeasibility of a large cohort study in sub-Saharan Africa assessed through a four-country study(Co-Action Publishing, 2015-05-25) Dalal, Shona; Holmes, Michelle D.; Laurence, Carien; Bajunirwe, Francis; Guwatudde, David; Njelekela, Marina; Adebamowo, Clement; Nankya-Mutyoba, Joan; Chiwanga, Faraja S.; Volmink, Jimmy; Ajayi, Ikeoluwapo; Kalyesubula, Robert; Reid, Todd G.; Dockery, Douglas; Hemenway, David; Adami, Hans-OlovBackground: Large prospective epidemiologic studies are vital in determining disease etiology and forming national health policy. Yet, such studies do not exist in sub-Saharan Africa (SSA) notwithstanding the growing burden of chronic diseases. Objective: We explored the feasibility of establishing a large-scale multicountry prospective study at five sites in four sub-Saharan countries. Design: Based on country-specific considerations of feasibility, Nigeria enrolled health care professionals, South Africa and Tanzania enrolled teachers, and Uganda enrolled village residents at one rural and one periurban site each. All sites used a 6-month follow-up period but different approaches for data collection, namely standardized questionnaires filled out by participants or face-to-face interviews. Results: We enrolled 1415 participants from five sites (range 200489) with a median age of 41 years. Approximately half had access to clean-burning cooking fuel and 70% to piped drinking water, yet 92% had access to a mobile phone. The prevalence of chronic diseases was 49% among 45- to 54-year-olds and was dominated by hypertension (21.7% overall) ranging from 4.5 to 31.2% across sites and a serious injury in the past 12 months (12.4% overall). About 80% of participants indicated willingness to provide blood samples. At 6-month follow-up, 68% completed a questionnaire (45 to 96% across sites) with evidence that mobile phones were particularly useful. Conclusions: Our pilot study indicates that a large-scale prospective study in SSA is feasible, and the burden of chronic disease in SSA may already be substantial necessitating urgent etiologic research and primary prevention.
- ItemNon-communicable diseases in Sub-Saharan Africa : the case for cohort studies(Public Library of Science, 2010-05-11) Holmes, Michelle D.; Dalal, Shona; Volmink, Jimmy; Adebamowo, Clement A.; Njelekela, Marina; Fawzi, Wafaie W.; Willett, Walter C.; Adami, Hans-OlovWe believe there is an urgent need for longitudinal cohorts based in sub-Saharan Africa (SSA). This conclusion is drawn from the fact that non-communicable diseases (NCDs) cause a large and growing disease burden (please see Box 1) [1–6]. In the past, public health in SSA has focused on communicable diseases. The advent of HIV/AIDS reinforced this image of infections as SSA’s major health burden. However, NCDs, including cardiovascular diseases, mental illnesses, trauma, cancer, and diabetes, are now major sources of morbidity and mortality and are projected to overtake infectious diseases by 2030 [7,8]. We argue that SSA lacks adequate resources to respond to this problem. Prospective cohort studies can be used to study multiple complex diseases and risk factors simultaneously over an individual’s lifetime. Such studies have proved crucial in understanding the etiology, course, and outcome of NCDs in other populations and have informed the design of prevention programs. In addition, cohort studies provide an incomparable resource for the training of public health researchers. Because the payoff from cohort studies continues—and often grows—over time, they are a long-term investment in public health. In order to highlight the potential impact of cohort studies in SSA, we compared published literature on NCDs from longitudinal studies in high-income countries to publications from Africa. Further, we estimated the costs of establishing cohort studies in SSA and describe the response needed to correct the disparities in research investment between SSA and the world’s more wealthy regions.
- ItemUrban and rural prevalence of diabetes and pre- diabetes and risk factors associated with diabetes in Tanzania and Uganda(Taylor & Francis Open, 2016) Chiwanga, Faraja S.; Njelekel, Marina A.; Diamond, Megan B.; Bajunirwe, Francis; Guwatudde, David; Nankya-Mutyoba, Joan; Kalyesubula, Robert; Adebamowo, Clement; Ajayi, IkeOluwapo; Reid, Todd G.; Volmink, Jimmy; Laurence, Carien; Adami, Hans-Olov; Holmes, Michelle D.; Dalal, ShonaENGLISH SUMMARY : Background: The increase in prevalence of diabetes and pre-diabetes in sub-Saharan Africa underlines the importance of understanding its magnitude and causes in different population groups. We analyzed data from the Africa/Harvard Partnership for Cohort Research and Training (PaCT) studies to determine the prevalence of diabetes and pre-diabetes and risk factors associated with diabetes. Methodology: Participants were randomly selected from peri-urban (n 297) and rural (n 200) communities in Uganda, and teachers were recruited from schools (n 229) in urban Tanzania. We used a standardized questionnaire to collect socio-demographic and self-reported disease status including diabetes status. Blood glucose was also measured after participants fasted for 8 h. We used standard protocols for anthropometric and blood pressure measurement. Results: The overall prevalence of diabetes was 10.1% and was highest in rural Ugandan residents (16.1%) compared to teachers in Tanzania (8.3%) and peri-urban Ugandan residents (7.6%). The prevalence of pre-diabetes was 13.8%. The prevalence of self-reported diabetes was low across all sites, where 68% of participants with diabetes were not captured by self-report. In ultivariable logistic regression analysis, family history (OR 2.5, 95% CI: 1.1, 5.6) and hypertension (OR 2.3, 95% CI: 1.1, 5.2) were significantly associated with diabetes. Conclusions: The prevalence of diabetes and pre-diabetes in Uganda and Tanzania is high, differs markedly between population groups, and remains undiagnosed in an alarmingly high proportion of individuals. These findings highlight the need for large-scale, prospective studies to accurately quantify the burden and identify effective intervention and treatment strategies across diverse African populations.
- ItemUrban–rural and geographic differences in overweight and obesity in four sub-Saharan African adult populations : a multi-country cross-sectional study(BioMed Central, 2016-10-28) Ajayi, IkeOluwapo O.; Adebamowo, Clement; Adami, Hans-Olov; Dalal, Shona; Diamond, Megan B.; Bajunirwe, Francis; Guwatudde, David; Njelekela, Marina; Nankya-Mutyoba, Joan; Chiwanga, Faraja S.; Volmink, Jimmy; Kalyesubula, Robert; Laurence, Carien; Reid, Todd G.; Dockery, Douglas; Hemenway, David; Spiegelman, Donna; Holmes, Michelle D.ENGLISH SUMMARY : Background: Overweight and obesity are on the rise in developing countries including sub-Saharan Africa. We undertook a four-country survey to show the collective burden of these health conditions as they occur currently in sub-Saharan Africa and to determine the differences between urban and rural populations and other socioeconomic factors. Methods: Participants were nurses in two hospitals in Nigeria (200), school teachers in South Africa (489) and Tanzania (229), and village residents in one peri-urban (297) and one rural location in Uganda (200) who completed a standardised questionnaire. Their height and weight were measured and body mass index calculated. Factor analysis procedure (Principal component) was used to generate a wealth index. Univariate and multivariate analyses with binary logistic regression models were conducted to examine the associations between potential correlates and the prevalence of overweight and obesity with 95 % confidence intervals. Results: The prevalence of overweight and obese (combined) was 46 %, 48 %, 68 %, 75 % and 85 % in rural Uganda, peri-urban Uganda, Nigeria, Tanzania and South Africa (SA), respectively. Rural Uganda, Peri- urban Uganda, Nigeria, Tanzania and SA had obesity prevalence of 10 %, 14 %, 31 %, 40 % and 54 %, respectively (p < 0.001). Overall, prevalence of overweight was 374 (31 %) and obesity, 414 (34 %). Female sex was a predictor of overweight and obesity (combined) in peri-urban Uganda [AOR = 8.01; 95 % CI: 4.02, 15.96) and obesity in rural Uganda [AOR = 11.22; 95%CI: 2.27, 55.40), peri-urban Uganda [AOR = 27.80; 95 % CI: 7.13, 108.41) and SA [AOR = 2. 17; 95 % CI: 1.19, 4.00). Increasing age was a predictor of BMI > =25 kg/m2 in Nigeria [Age > =45 - AOR = 9.11; 95 % CI: 1.72, 48.16] and SA [AOR = 6.22; 95 % CI: 2.75, 14.07], while marital status was predictor of BMI > =25 kg/m2 only in peri-urban Uganda. [Married - AOR = 4.49; 95 % CI: 1.74, 11.57]. Those in Nigeria [AOR = 2.56; 95 % CI: 1.45, 4.53], SA [AOR = 4.97; 95 % CI: 3.18, 7.78], and Tanzania [AOR = 2.68; 95 % CI: 1.60, 4.49] were more likely to have BMI > =25 kg/m2 compared with the rural and peri-urban sites. Conclusion: The high prevalence of overweight and obesity in these sub-Saharan African countries and the differentials in prevalence and risk factors further highlights the need for urgent focused intervention to stem this trend, especially among women, professionals and urban dwellers.