Factors associated with hypertension in Nigerian civil servants

BACKGROUND. Study of hypertension in segments of West African populations in transition toward Westernization may lead to better understanding of the high risk for hypertension among Westernized blacks. METHODS. Five hundred fifty-nine urban civil servants, ages 25-54, were recruited from six ministries of Bendel State, Nigeria. Blood pressure, physical measurements, urinary protein and glucose, fasting blood glucose, and demographic data were collected at the workplace. Subjects were classified as senior staff (professionals or administrators) or junior staff (non-administrators). RESULTS. Among 172 male senior staff, the age-adjusted rate of hypertension (diastolic blood pressure > or = 90 mm Hg, systolic blood pressure > or = 140 mm Hg, or on an antihypertensive medication) was 43% and occurrence rose dramatically from 21 to 63% across age groups 25-34 to 45-54, respectively. Among 266 male junior staff, the age-adjusted rate of hypertension was 23%, and occurrence did not rise with age. Logistic regression showed that body mass index (kg/m2), age, alcohol drinking, and being senior staff were all independently related to hypertension in men. On the other hand, the age-adjusted rate of hypertension in 121 women was 20% and was significantly related only to body mass index. CONCLUSION. Male urban civil servants appeared to have a risk for hypertension similar to that of U.S. black males. Age, body mass index, alcohol drinking, and other unidentified factors related to higher socioeconomic status were strong determinants of hypertension in this population.     

Genetic association of five apolipoprotein polymorphisms with serum lipoprotein-lipid levels in African blacks

Genetic studies carried out mainly in European and European-derived populations have shown that common polymorphisms in genes coding for apolipoproteins are significant determinants of serum lipoprotein-lipid levels variation. However, except for a few sporadic studies, the distribution of apolipoprotein polymorphisms and their association with serum lipoprotein-lipid levels have not been evaluated systematically in African or African-derived populations. In this investigation we have studied five apolipoprotein polymorphisms, including APOA1/MspI-75 bp, APOA1/MspI+83 bp, APOC3/PvuII, APOE, and APOH in 786 Africans (493 men, 293 women) from Nigeria. The sample is comprised of Nigerian civil servants consisting of 462 junior staff (less affluent) and 324 senior staff (more affluent) where staff status is a correlate of their socioeconomic status. We first examined genetic associations in the total sample stratified by gender to determine the role of apolipoprotein polymorphisms in affecting serum lipid profile in the general population, and then by staff status to evaluate possible gene-environment interactions. In the total sample, the APOC3/PvuII polymorphism showed significant effect on HDL-cholesterol (P = 0.029) and HDL3-cholesterol (P = 0.009) in women, and the APOE polymorphism was significantly associated with total cholesterol (P = 0.031) and LDL-cholesterol (P = 0.0006) in women. Multiple regression analyses showed that the APOC3/PvuII polymorphism accounts for about 2 and 3% of the variation in HDL-cholesterol and HDL3-cholesterol, respectively, in women; while the APOE polymorphism accounted for about 5 and 6% of the variation in total- and LDL-cholesterol, respectively, in women. Whereas the association of the APOE polymorphism was independent of the staff status, the significant affect of the APOC3/PvuII polymorphism on HDL- and HDL3-cholesterol was confined to senior staff women where it explained about 7% of their variation. We also observed an interaction between staff and the APOH polymorphism in affecting cholesterol levels. The APOH polymorphism showed significant association with total cholesterol (P = 0.010) and LDL-cholesterol (P = 0.016) in senior staff women and explained about 7 and 5% of their phenotypic variations, respectively. These data indicate that gene-environment interaction may play an important role in affecting serum lipid profile in African populations.     

Normal values for metacarpal and phalangeal lengths in Nigerian children

Metacarpal and phalangeal lengths were measured on 1290 hand radiographs of Nigerian children, aged 3–16 years. The radiographs were obtained during a combined cross-sectional and longitudinal study of growth and development. There is a linear increase in tubular bone length with age in both sexes. The girls have higher values for all the bones up to the age of 13 years when the boys overtake them. Comparison of our data with those from North American children shows that the values amongst Nigerian children are higher than White, Black American and Mexican American children. Of particular note is the difference between Black American and Nigerian figures. It is postulated that the decreased metacarpophalangeal lengths in Black Americans compared with Nigerians may be due to gene dilution.     

Physical activity and cardiovascular risk factors in a developing population

PURPOSE: Noncommunicable diseases are emerging in developing countries. However, few studies have been conducted in those countries to evaluate the role of physical activity in the development of cardiovascular diseases. This study investigated physical activity and its relationship to risk factors for cardiovascular disease in a large population (N = 799) of civil servants from Benin City, Nigeria. METHODS: Physical activity levels were estimated by an interviewer-administered questionnaire, which determined the average hours per week over the past year spent in occupational and leisure activities. Time spent walking or biking to work was assessed as well. Other major measures included body mass index (BMI), waist-hip ratio (WHR), blood pressures, plasma insulin level, lipid profiles, and diet. RESULTS: More of the physical activity was attributed to occupational than to leisure activities. Compared with women, men had a higher activity level. No significant trend was observed across age groups. Male senior staff (a marker of higher socioeconomic status) had a lower physical activity level than male junior staff. Physical activity, especially time walking or biking to work, was inversely correlated with weight, BMI, WHR, blood pressures, insulin, total cholesterol, LDL and HDL cholesterol, and triglycerides in men, while such correlations were not consistent in women. In multivariate analysis in men, blood pressure and insulin were independently associated with BMI but not with walking, while an independent inverse association was seen between walking and BMI. CONCLUSION: Lack of physical activity was associated with adverse risk profiles for cardiovascular disease in this developing population.     

Black-White Differences in Hip Geometry

Previous studies have demonstrated that reduced thickness of the femoral neck and shaft cortex, a wider intertrochanteric region and a longer hip axis length were predictive of hip fracture among Caucasian women. We hypothesized that racial differences in these features of hip geometry may contribute to explaining the differences in hip fracture incidence between women of African origin and Caucasian women. We measured the cortical thickness and bone widths in 132 African-American women and 43 Nigerian women who were pair-matched on height (± 3 cm), age (± 5 years) and weight (± 3 kg) to 175 Caucasian women. Measures of cortical thickness were greater among women of African origin than Caucasian. Women of African origin had smaller bone widths and a shorter hip axis length than Caucasians. Several of these differences were independent of bone mineral density except for the cortical thickness of the femoral shaft. We conclude that women of African origin have thicker cortical bone of the hip, a shorter hip axis length and smaller intertrochanteric widths than Caucasians. Based on a model developed from hip fractures among Caucasian women, we predict that these observed racial differences could contribute to approximately a 25% decrease risk of hip fracture among blacks.     

Factors related to blood pressure among urban Nigerian workers

This cross-sectional study of urban, Nigerian civil servants found that age, body mass index, alcohol drinking and high socioeconomic status were all positively and independently related to blood pressure among 438 males. Among 121 females, only body mass index was significantly related to blood pressure.     

Does nondipping of blood pressure at night reflect a trait of blunted cardiovascular responses to daily activities?

Background: Individuals who fail to show a decline in blood pressure (BP) when asleep or at night (labeled nocturnal nondippers) are at elevated risk for hypertension and associated targetorgan damage.Purpose: We tested whether the well-established changes in BP exhibited in response to daily activities are also blunted in nocturnal nondippers.Methods: Cross-sectional study of 41 women and 56 men, aged 27 to 71 years, residing in Benin, Nigeria, enrolled in a health survey of civil servants. Ambulatory 24-hr BP monitoring was performed with concurrent diary recordings of physical activity level, posture, location, state of mental activity, interpersonal interaction, and mood obtained during the waking hours.Results: Nocturnal nondippers exhibited smaller cardiovascular responses to changes in posture (from lying to sitting or to standing, ps <.02), location (from home to work or to driving/riding in a car, ps < .02), mental activity (from relaxed to active, p =. 02), and mood (from feeling mellow to feeling elated-happy, p = .05) than did dippers. Statistical controls for posture substantially reduced the effects of nondipping status on responses to other daily activities and mood. Lack of systolic BP responsiveness to postural changes during the day is a strong predictor of nondipping status.Conclusions: Nondipping at night appears to extend to decreased cardiovascular responses to changes in activities during daytime hours. This work was supported by National Institutes of Health Grants HL44413 andHL44413-S1.     

Tracking of blood pressure and anthropometric measures in Nigerian children.

Persistence in ranks (tracking) for blood pressure and anthropometric measures over a one year period was examined in 208 Nigerian children (age 6-17 years). Systolic blood pressure tracked better than diastolic blood pressure (r = 0.52 to 0.72) and r = 0.25 to 0.55, respectively). For systolic blood pressure, 56.5%-70.6% of the Nigerian children remained in the top tertile after one year compared with 45.5%-69.2% for diastolic blood pressure. Weight showed the strongest correlation over the one year period (r = 0.88 to 0.97), whereas skinfolds demonstrated the weakest association (r = 0.54 to 0.82). The association between anthropometric measures at baseline and blood pressure one year later revealed for both males and females that height and weight were positively and significantly correlated with blood pressure.