Vascular Reactivity in Normotensive Male and Female Subjects in a Nigerian Population

Hypertension is a medical condition that does not have specific clinical manifestations until organ damage is set-in and its prevalence is said to be highest in Africa. The objective of this study is to assess and compare vascular reactivity in normotensive male and female Nigerians in order to screen for those at risk of developing hypertension.Thirty-six apparently healthy, young normotensive male and female subjects, aged 18 years – 37 years were exposed to cold pressor test (CPT). Systolic blood pressure (SBP) and diastolic blood pressure (DBP) were measured before and after exposure to the CPT. Blood pressure was determined by auscultatory method. Subjects were instructed to immerse one foot up to the ankle into ice slurry maintained at 4°C for 1 minute2. 11Vascular hyper- reactivity was determined as an increase in the subject's systolic or diastolic blood pressure 15 mmHg after exposure to the CPT. In the parameters measured, SBP and DBP increased significantly (p< 0.0001) after exposure to CPT. There were no significant differences (p> 0.05) in SBP and DBP responses to the CPT between the male and female subjects. However, Systolic hyper-reactivity was observed in 56% of the male subjects while 50% of them demonstrated diastolic hypereactivity. On the other hand, 50% of the female subjects showed systolic hyper- reactivity while 56% of them demonstrated diastolic hyper-reactivity, indicating vulnerability of these individuals to development of hypertension in the future. Since at least,half (50%) of the study population were hyper-reactive in their SBP or DBP, drastic action on preventive measures should be targeted at those at risk of developing hypertension, so as to stem the rising incidence and prevalence of hypertension in Africa.

Key Words: Vascular Reactivity, Cold Pressor test, Hypertension