Nutritional status, socio-economic status, heart rate, and blood pressure in African school children and adolescents.

OBJECTIVES: To determine the impact of gender, nutritional anomalies, puberty and socio-economic status on the levels of blood pressure, fat distribution and heat rate in African school children and adolescents. This study also identified the risk factors of arterial hypertension in African adolescents. DESIGN: A cross-sectional study carried out between April and July 1996. SETTING: Randomly selected schools of the semi-urban area of Kinshasa Province, capital of the Democratic Republic of Congo. SUBJECTS: 1535 school children and adolescents. OUTCOME MEASURE: Height, weight, waist circumference, hip circumferences, blood pressure and heart rate were measured. Body mass index, and waist-hip ratio, and Z-scores of NCHS/WHO for different levels of malnutrition were calculated for gender and age. RESULTS: High rates of malnutrition forms and overweight/obesity coexisted. Boys with chronic malnutrition had significant higher blood pressure levels. Children with pooled types of malnutrition had higher waist circumference, waist-hip ratio and heart rate values. Children from the low socio-economic status had higher blood pressure and heart rate levels than those from high socio-economic status. Overweight/obesity was more (p<0.05) prevalent among female adolescents (68.5%) than male adolescents (24%). Obese male adolescents had higher blood pressure and heart rate levels than their non-obese male counterparts. 39% of variations of systolic blood pressure of male adolescents were explained only by body mass index, whereas 56% of variations of diastolic blood pressure of male adolescents were explained only by age. Only low socio-economic status was identified as a significant risk factor of arterial hypertension among these African adolescents (OR=1.2; 95% CI 1.1 to 1.3; p<0.01). CONCLUSION: Intervention strategies to combat poverty and high cardiometabolic risk may need to be developed for these African school children and adolescents.

Hematocrit and stroke in black Africans under tropical climate and meteorological influence.

OBJECTIVES: To assess the relationship between hematocrit and risk of fatal and non-fatal stroke in conjunction with meteorological variations. DESIGN: Prospective study of a series of Africans living in Kinshasa, Congo, followed up for 5 years. SUBJECTS: A total of 1,032 unselected patients consecutively admitted to hospitals for acute stroke. Main outcome measures. Fatal and non-fatal ischemic or hemorrhagic strokes. The association of hematocrit with stroke morbidity and mortality and meteorological variables were evaluated by simple or multiple linear regression and logistic regression. RESULTS: Patients were aged 53.7 +/- 12.1 years. Hematocrit was mostly correlated with mean ambient air temperature (r = 0.124; p < 0.001) and atmospheric pressure at 6 a.m GMT (r = 0.157; p < 0.001). Patients with hematocrit > 40% presented the highest levels of systolic blood pressure, fibrinogen, body temperature, resting heart rate, duration of coma and incidence of all stroke types and ischemic stroke (p < 0.001). Hematocrit > 40% was associated with stroke mortality (Odds ratio, 6.2, 4.5-8.6; p < 0.001). The risk of stroke mortality was multiplied by 21, 18.3 and 4.2 in conditions of a mean ambient air temperature > 28 degrees C, atmospheric pressure 975-977 mm Hg and body temperature > 37 degrees C respectively. CONCLUSIONS: Our study suggests that higher hematocrit is associated with an increased risk of stroke morbidity and mortality, particularly ischemic stroke at noon. This risk is probably mediated by increased susceptibility of African older hypertensive subjects to meteorological variations.