Association of urinary sodium excretion with blood pressure and risk factors associated with hypertension among Cameroonian pygmies and bantus: a cross-sectional study

Abstract

BackgroundHigh salt intake increases blood pressure (BP) and hypertension risk. This study aimed to examine association of urinary sodium excretion with BP and hypertension correlates among Cameroonian pygmies under hunter-gatherer subsistence mode and Bantus, living in urban area under unhealthy behavioral habits.MethodsIn this cross-sectional cluster sampling study, we randomly enrolled rural pygmies living in Lolodorf and urban Bantus living in Douala. The World Health Organization steps questionnaire was used to collect socio-demographic and lifestyle data. Height, weight, BP and single overnight spot urine samples were obtained in all participants. BP was measured in triplicate. Urinary sodium and potassium excretion was determined by flame photometry. Data were recorded and analyzed using SPSS 16.0.ResultsWe included 150 Pygmies and 150 Bantus aged 38 ± 12 years and 33 ± 11 years, respectively (p < 0.0001). Compare to Bantus, pygmy’s height and weight were respectively: 1.54 ± 0.09 m vs 1.72 ± 0.12 m; and 54.4 ± 9.2 kg vs 77.2 ± 14.8 kg, all p < 0.0001. Age-standardized prevalence of hypertension was 3.3% among Pygmies and 28% among Bantus (p < 0.0001). Age-adjusted systolic and diastolic BP were lower in Pygmies than in Bantus (107 ± 12 vs 119 ± 17 mmHg and 71 ± 11 vs 78 ± 13 mmHg respectively, all P < 0.0001). BP increased with age but to a lesser extent in Pygmies (all p < 0.01). Urinary sodium excretion was lower in Pygmies than in Bantus (46.9 ± 32.4 vs 121.5 ± 61.0 mmol/l, p < 0.0001). Systolic and diastolic BP were positively associated with urinary sodium excretion in Bantus (all p < 0.05). In the two groups, urinary potassium excretion was similar, and was not related to blood pressure. In the total study group and in Bantus taken separately, urinary sodium excretion was higher in hypertensive than in normotensive subjects. Multivariable logistic regression showed that urinary sodium excretion, Bantu status and age emerged as independent determinants of hypertension in the whole study group (OR (95%CI): 1.012 (1.005–1.018); 11.408 (3.599–36.165); 1.095 (1.057–1.135) respectively, p < 0.0001).ConclusionHunter-gatherer pygmies exhibit low level of urinary sodium excretion related to low rate of hypertension and slower BP increase with age. Salt intake was a major driver of hypertension in our study population. Our findings highlight the need of efforts to implement nationwide prevention programs promoting risk factor screening and healthier lifestyles including reduction of dietary salt intake in Cameroonian.

Associated Factors of Hypertension in Women and Men in Vietnam: A Cross-Sectional Study

“…Salt intake was found as a key factor of hypertension in previous studies [37]. However, in the current study, the association was only found in women, but not in men.…”

“…In a previous study in Vietnam, salt consumption was not significantly associated with high BP at the national level, but the association differed between urban and rural areas in Vietnam [61]. However, the evidence of this association was consistently found in other countries, namely in Brazil [62], China [63], in Cameroon [37]. Moreover, the long term effect of reduction in salt intake on population BP and CVD was summarized from several randomized trials [64,65,66].…”

“…In both women and men, those with older age were more likely to have hypertension. It was summarized that age and gender were the major risk factors of hypertension in Vietnam and other countries [15,36,37,38,39,40,41,42].…”

Blood pressure and burden of hypertension in Cameroon, a microcosm of Africa

“…The 20 studies [41][42][43][44][45][46][47][48][49][50][51][52][53][54][55][56][57][58][59] used objective measure of the hypertension (Supplemental Table 1, http://links. lww.com/HJH/B114).…”

“…Nine and eight of the 20 studies included Yaoundé (capital city) and Douala (main economic city) of Cameroon, respectively. The study quality scores ranged from 8 [45] to 18 [57].…”