Cardiovascular risk factors in Sub-Saharan African women
Insights from the TAHES study
Abstract
Summary:Background: Cardiovascular risk factors (CVRF) are associated with major cause of death and disability in Sub-Saharan Africa, especially in women. The contribution of obstetrical, psychological, and socio-economic factors in CVRF are not yet well described in Africa. We aimed to compare the prevalence of CVRF between men and women, and to determine the factors associated to these sex-related differences. Patients and methods: A cross-sectional study was conducted on the 2019 data of the TAHES cohort in a geographically defined general population in Benin. A standardized questionnaire adapted from the World Health Organization (WHO) STEPS instrument was used to collect data. Univariate and multivariate analysis has been performed to determine CVRF differences in both sexes. Women-specific logistic regressions have been performed on CVRF previously identified as positively associated to female sex, to assess their association with socio-economic, psychological, and obstetrical factors. Results: We included 1583 patients, with a median age of 39 years [range: 32–53 years]. Prevalence of diabetes (1.2% vs. 3.4%, p=0.0042), abnormal kidney function (15.5% vs. 8.4%, p=0.0002), obesity (12.5% vs. 4.1%, p<0.0001), tobacco-smoking (3.4% vs. 14.1%, p<0.0001) and reduced physical activity (69.9% vs. 50.7%, p<0.0001) differed significantly between women and men, respectively. In multivariate analysis, female sex was independently and significantly associated with obesity, anxiety, depression and reduced physical activity. Number of pregnancies was associated with a reduced physical activity. Hypertension was associated with gestational hypertension. Conclusions: Obesity and reduced physical activity are significantly and independently more frequent in Beninese women than the male counterparts. Hypertension prevalence in Benin is alarming in both sexes. Targeted prevention strategies against obesity, gestational hypertension and sedentary lifestyle are advocated in African women.
Introduction
An epidemiological transition is ongoing in SubSaharan Africa (SSA), from communicable to non-communicable diseases [1]. Currently, the risk of death secondary to non-communicable diseases is the highest in African countries for both sexes [2]. Non-communicable diseases are rising quickly, and will be the first cause of death in Africa in 2030 [3]. Among them, cardiovascular diseases have a heavy burden [3]. Cardiovascular diseases are influenced by numerous cardiovascular risk factors (CVRF), such as age, obesity, hypertension, dyslipidemia, diabetes, abnormal kidney function [4, 5] as well as psychosocial factors [4, 6].
Women in SSA have the highest death rate due to hypertension in the world [7]. They also have the highest impact of obesity on DALY [7]. Despite all those data, very few studies have been performed to determine cardiovascular risk factors prevalence and their associated factors in this population. Moreover, the link between cardiovascular issues and obstetrical status in this area remains unclear, while the birth rate is high and pregnancy could lead to cardiovascular diseases [8]. Countries in SSA are mostly categorized as low-income countries with poor access to drugs. Prevention should play an important role in their public health politics to limit the social and economic impact of cardiovascular diseases.
Our primary objective was to describe CVRF prevalence in an SSA community and to compare them between men and women. Our secondary objective was to determine clinical and socio-economic factors associated with CVRF, and their specificities according to sex.
Patients and methods
The TAHES cohort
TAHES is an epidemiological survey started in 2015 and conducted in a rural community of Benin (Tanvé), focused on cardiovascular diseases. The protocol and its feasibility were reported. All patients were recruited by a door-to-door approach, whatever was their health condition. They were invited to undergo a medical examination the day after their inclusion at the local health center. A standardized questionnaire adapted from the World Health Organization (WHO) STEPS instrument was used to collect data [9]. In addition to the standard questionnaire, information on previous pregnancies and creatinine measurement were collected. All data were anonymized. This study was conducted in accordance with General Data Protection Regulation (GDPR) laws and Helsinki’s human rights declaration and subject consent required. Our study protocol was declared to the local ethic comity (visa N° 0411/CLERB-UP/P/SP/R/SA).
Study population
A cross-sectional study on the 2019 data of the TAHES cohort was performed. In 2019, obstetrical and renal data have been recorded for the first time. All consecutive patient ≥25 years were included. Younger citizens were not included, considering the very low prevalence of cardiovascular disease below 25 years. Exclusion criterion were a history of severe mental deficiency, a current pregnancy, and living in Tanvé area for less than 6 months.
Socio-economic and demographic data
Socio-economic data were marital status, education level, professional category, frequency of fruits and vegetables intakes, frequency of salt consumption, alcohol intake during the last 30 days, current smoking, and weekly-physical activity. All data were declared by subjects. Demographic data were sex and age.
Clinical data
Clinical data were obstetrical history, anthropometric data, psychological status, blood pressure on both arms, diabetes, and abnormal kidney function.
Obstetrical history
Obstetrical data consisted in the number of pregnancies, age at the first and the last pregnancy and gestational hypertension. Missing data have not been replaced. Late pregnancy was defined as a first and/or a last pregnancy at 35 years old or older.
Anthropometric data
Anthropometric data consisted in weight, height, and Body mass index (BMI). BMI value was determined as: BMI=weight (kg)/height (m)2.
Psychological status
Psychological status was determined by 9-items Goldberg scale for anxiety and depression. At least 5 symptoms in anxious dimension were necessary to consider the person as anxious. At least 2 symptoms in depressive dimension were necessary to consider the person as depressed.
High blood pressure
ESC recommendations were used to define high blood pressure. Three measures were realized on each arm. The two last measures were averaged for each arm. The highest mean was considered as the person’s blood pressure value. Hypertension was defined as a history of hypertension requiring medical treatment or a systolic blood pressure ≥140 mmHg/a diastolic blood pressure ≥90 mmHg during physical examination.
Diabetes
Diabetes was defined as a current intake of antidiabetic drugs or a fasting glycemia equal or above 1.26 g/l. Only one fasting glycemia measurement was performed during data collection.
Abnormal kidney function
Abnormal kidney function was defined as an estimated glomerular filtration rate (eGFR) ≤60 ml/min/1.73 m2. CKD-Epi formula was used, adjusted on sex, ethnicity and creatinemia value. Creatinemia values from subjects with technical issue were missing and not replaced (n=238).
Statistical analysis
Variable’s distribution was defined as not normal by Shapiro-Wilk test. Continuous variables were reported using median (interquartile range) and categorical variables using n (percentage). Qualitative variables were compared using Pearson’s χ2 or Fisher exact test, while Mann-Whitney test was used to compare quantitative variables according to sex. Odds-ratio (OR) with their 95% confidence interval ([95%CI]) and their p-value were determined for each variable according to sex. A p-value ≤0.25 at univariate analysis was required for inclusion in multivariate analysis.
Backward stepwise logistic regressions were performed on CVRF and socio-economic variables in general population, to confirm their significant and independent association with female sex. A second logistic regression was performed focusing on CVRF in female population, to include women-specific factors, such as obstetrical data. OR with 95%CI and p-value were determined (p-value threshold ≤0.05).
All statistical analyses were performed on JMP Pro (version 16.0.0, SAS INSTITUTE JMP, Brie Comte Robert, France), and JASP (version 0.14.0.1, Amsterdam University, Amsterdam, the Netherlands).
Results
General population analysis
Overall, 1 583 subjects (973 women, 61.5%) were included. Population characteristics are displayed in Tables I and II. Diabetes, alcohol consumption and smoking were significantly more prevalent in male population. Women were significantly more frequently obese (12.5%), anxious (11.7%), depressed (22.4%), with abnormal kidney function (15.5%), no education (74.7%) and a limited physical activity (<3 days a week) (69.9%). Age, history of hypertension, salt consumption and fruits/vegetables intake were similar in both sexes. Means of transports in the general population are car (5%), motocycle (61.3%) and bike (22.2%). Men used significantly more bikes and motocycle than women (p<0.001), while no significant difference was found regarding car (p=0.544).
Multivariate analysis results are displayed in Table III. Female sex was significantly and independently associated with obesity (p<0.001) and reduced physical activity (p<0.001), while association to abnormal kidney function had borderline results (p=0.057). Significant association was also found with socio-economic variables, such as anxiety (p<0.001) and having no education (p<0.001).
Cardiovascular risk factors in women
In the female population, median number of pregnancies was 6 [4, 5, 6, 7, 8] and median age at first pregnancy was 20 [17, 18, 19, 20, 21, 22]. We found that 33.3% of women have been concerned by a late pregnancy, and 10.4% by gestational hypertension. In a specific analysis limited to women, we added obstetrical data along with CVRF. Obesity was significantly and independently associated with age (OR 0.972 [0.958–0.985], p<0.001) and hypertension (OR 2.956 [2.042–4.279], p<0.001). Limited physical activity was significantly and independently associated with increased number of pregnancies, monthly amount of alcohol consumption, limited vegetables intake and being a farmer or an independent occupation (Figure 1). Hypertension was significantly and independently associated with age, obesity and gestational hypertension (Figure 2). Regarding LEAD in women population, no specific associated factor has been found.
Discussion
To the best of our knowledge, our study is the first to compare the CVRF in the two sexes in a SSA community. Our study shows differences between men and women regarding cardiovascular risk factors prevalence. Compared to male, female participants had significantly and higher rates of obesity, abnormal kidney function and limited physical activity. Hypertension prevalence was similarly high in both sexes.
Hypertension and obesity prevalence are higher in our population than the 13–14% and 9–27% reported by literature [10, 11, 12]. On the other hand, chronic kidney disease and smoking prevalences are consistent with the 15.8–17% and the 0.4–71% respectively reported [11, 13]. Kerekou et al. noticed a higher limited physical activity prevalence than ours, from 51.8% for men to 62.2% for women [14]. There is an important discrepancy regarding diabetes prevalence, ranging from 0% to 16% elsewhere in SSA [15]. However, our data regarding diabetes are consistent with Price et al. results, who found a 2–3% prevalence in a >30 years old population [10]. Thus, LEAD prevalence is higher than CHD prevalence, which is consistent with previous studies on European and North-American populations [16].
By comparison with European countries, our general population is less concerned by diabetes (2% vs. 11%) [17], obesity (9% vs. 23%) [18] and limited physical activity (10.8% vs. 30%) [19]. However, hypertension prevalence is similar (32% vs. 30–45%) [20]. We can also highlight the low prevalence of smoking in our population, while the worldwide one is established at 22.3% by the World Health Organization [21]. Smoking is still not well considered in SSA countries, which could explain this result.
We found that women had significantly and independently higher rates of obesity and limited physical activity. Obesity was more frequent in younger women and those with hypertension. Regarding the high prevalence of sedentary lifestyle and its association to female sex, specific educational strategies must be implemented to promote physical activity among women, and especially in those with no pregnancies and/or obesity. Public health politics in SSA countries should adjust to the rise of obesity and limited physical activity [22].
Hypertension prevalence was not different according to sex. However, the prevalence was similar to the worldwide one, while previously projected prevalence in Africa was 17.4% in 2025 [12]. This high prevalence is alarming, considering hypertension as the sixth risk factor in term of attributable global burden disease in western SSA countries [23]. Regarding the high salt-consumption in this area, specific preventive actions are mandatory. In addition to hypertension high prevalence, we can notice that fruit and vegetables intakes are quite low. Some studies tend to show an inverse association between risk of hypertension and fruits and vegetables consumption [24]. This result is consistent with the current recommendation of both American Heart Association and European Society of Cardiology regarding a high-intake of vegetables and fruits in hypertension treatment [25, 26].
We decided to perform a women-only multivariate analysis on hypertension. We showed that it was linked to gestational hypertension, which prevalence is higher in our population than previously reported in European and Northern-American studies [27, 28, 29]. A bias may be induced by the fact that the questionnaire does not distinguish hypertension occurring during pregnancy from chronic hypertension; however, this high prevalence should advocate for a targeted action.
Limitations
Our study was based on a general population and reported original data. However, limitation needs to be acknowledged. First, our population lived in a rural area, limiting extrapolation of the present results to urban areas.
Collected data did not include several variables, such as HIV status, dyslipidemia, familial cardiovascular disease history. Some obstetrical data (history of pre-eclampsia, birth weight of infant, gestational diabetes, prematurity) were also lacking. Although numerous declarative data have been included and are submitted to recall bias, this effect has been limited by using WHO STEP protocol and systematic answers control during inclusion. Finally, study design allowed us to show association between variables, not to define risk factors.
Conclusions
In sub-Saharan Africa, the prevalence of obesity and limited physical activity is high and significantly higher than male counterparts. In addition, the number of pregnancies in Beninese women seem to be associated with CVRF like limited physical activity, while gestational hypertension is associated with hypertension. Longitudinal analysis should be performed to confirm those associations. In the meantime, high prevalence of hypertension, limited physical activity and obesity in a young-age female population should lead to targeted public-health actions, focusing on healthy diet and physical activity.
References
1 . Global Burden of Disease 2019. [cited 2021 May 20]. Available from: https://www.thelancet.com/infographics/gbd-2019
2 . NCD Countdown 2030: worldwide trends in non-communicable disease mortality and progress towards Sustainable Development Goal target 3.4. Lancet. 2018;392(10152):1072–88.
3 . Global status report on noncommunicable diseases 2010 [Internet]. World Health Organization, 2011. Available from: https://apps.who.int/iris/handle/10665/44579
4 . Cardiovascular diseases (CVDs). [cited 2021 Jun 2]. Available from: https://www.who.int/news-room/fact-sheets/detail/cardiovascular-diseases-(cvds)
5 . Cardiovascular disease risk factors in chronic kidney disease: overall burden and rates of treatment and control. Arch Intern Med. 2006;166(17):1884–91.
6 . Anxiety and hypertension: is there a link? A literature review of the comorbidity relationship between anxiety and hypertension. Curr Hypertens Rep. 2019;21(9):66.
7 Global burden of cardiovascular diseases and risk factors, 1990–2019: update from the GBD 2019 study. J Am Coll Cardiol. 2020;76(25):2982–3021.
8 . Pre-eclampsia and risk of cardiovascular disease and cancer in later life: systematic review and meta-analysis. BMJ. 2007;335(7627):974.
9 Feasibility of a cardiovascular cohort in a Sub-Saharan Africa community: preliminary report of the pilot project TAHES (Tanvè Health Study) in Benin. Glob Health Action. 2017;10(1):1270528.
10 Prevalence of obesity, hypertension, and diabetes, and cascade of care in sub-Saharan Africa: a cross-sectional, population-based study in rural and urban Malawi. Lancet Diabetes Endocrinol. 2018;6(3):208–22.
11 Non-communicable diseases in sub-Saharan Africa: what we know now. Int J Epidemiol. 2011;40(4):885–901.
12 . Current and projected prevalence of arterial hypertension in sub-Saharan Africa by sex, age and habitat: an estimate from population studies. J Hypertens. 2011;29(7):1243–52.
13 . Burden of chronic kidney disease on the African continent: a systematic review and meta-analysis. BMC Nephrol. 2018;19(1):125.
14 . P8 enquête de prévalence de l’inactivité physique en médecine externe au CNHU/HKM de Cotonou. Diabetes & Metabolism. 2014;40 Suppl 1:A32. https://doi.org/10.1016/S1262-3636(14)72302-X
15 Diabetes in sub-Saharan Africa: from clinical care to health policy. Lancet Diabetes Endocrinol. 2017;5(8):622–67.
16 . Burden of coronary artery disease and peripheral artery disease: a literature review. Cardiovasc Ther. 2019;2019:8295054.
17 . IDF Diabetes Atlas 2021. [cited 2022 Oct 24]. Available from: https://diabetesatlas.org/atlas/tenth-edition/
18 . New WHO report: Europe can reverse its obesity “epidemic”. [cited 2022 Oct 24]. Available from: https://www.who.int/europe/news/item/03-05-2022-new-who-report-europe-can-reverse-its-obesity–epidemic
19 2021 ESC Guidelines on cardiovascular disease prevention in clinical practice. Eur Heart J. 2021;42(34):3227–337.
20 2018 ESC/ESH Guidelines for the management of arterial hypertension. Eur Heart J. 2018;39(33):3021–104.
21 . Tobacco. [cited 2022 Aug 9]. Available from: https://www.who.int/news-room/fact-sheets/detail/tobacco
22 . NOW AND THEN: the global nutrition transition: the pandemic of obesity in developing countries. Nutr Rev. 2012;70(1):3–21.
23 A comparative risk assessment of burden of disease and injury attributable to 67 risk factors and risk factor clusters in 21 regions, 1990–2010: a systematic analysis for the Global Burden of Disease Study 2010. Lancet. 2012;380(9859):2224–60.
24 A clinical trial of the effects of dietary patterns on blood pressure. DASH Collaborative Research Group. N Engl J Med. 1997;336(16):1117–24.
25 2019 ACC/AHA guideline on the primary prevention of cardiovascular disease: executive summary: a report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines. Circulation. 2019;140(11):e563–95.
26 2018 ESC/ESH Guidelines for the management of arterial hypertension: The Task Force for the management of arterial hypertension of the European Society of Cardiology (ESC) and the European Society of Hypertension (ESH). Eur Heart J. 2018;39(33):3021–104.
27 2018 ESC Guidelines for the management of cardiovascular diseases during pregnancy. Eur Heart J. 2018;39(34):3165–241.
28 Report of the national high blood pressure education program working group on high blood pressure in pregnancy. Am J Obstet Gynecol. 2000;183(1):S1–22.
29 . Descriptive epidemiology of chronic hypertension, gestational hypertension, and preeclampsia in New York State, 1995–2004. Matern Child Health J. 2014;18(4):829–38.
