Anthropometric predictors of elevated prostate specific antigen among rural and urban Nigerians: a population-based study

BACKGROUND

Obesity has been associated with incidence and mortality of carcinoma of the prostate (CaP), but the relationship of BMI to CaP risk remains controversial across populations.

OBJECTIVE

To describe the anthropometric correlates of elevated prostate specific antigen in Nigeria, a low-incidence region for CaP that currently reports rising incidence.

SUBJECTS AND METHODS

Weight, height and skin fold thickness were measured for men, aged 40 years and older. Waist-to-hip ratio (WHR) and body mass index (BMI) were computed. Prostate specific antigen (PSA) status and prostate size were determined. Mean anthropometric indices were compared across groups using Student's t-test, association between anthropometry and PSA was by Spearman's correlation, and mean PSA was tested for linearity across tertiles of anthropometry. Prediction of elevated PSA was determined by multivariate logistic regression controlling for age and prostate size.

RESULTS

Of 350 consecutive men contacted, 281(80.3%) completed the survey, mean age 56.9(13.5) years, and elevated PSA prevalence 31(11.0 %). WHR was 0.92 for rural and urban men, BMI (22.9 vs 24.7, p<0.002, and skin fold thickness was lower for rural men. PSA correlated directly with age, r=0.360, p<0.0001 and negatively with height, r=-0.136, p<0.023. WHR remained a significant predictor of elevated PSA,[OR 3.04 (95% CI 1.13 - 8.15)], after adjusting for age and enlarged prostate.

CONCLUSION

Central adiposity may be a more important predictor of elevated PSA than BMI in this population. There is need to investigate the role of hormonal, metabolic, and genetic correlates of central adiposity in carcinoma of the prostate risk in this population.

Microalbuminuria and associated factors in newly diagnosed diabetics

Diabetic nephropathy is a common cause of end-stage renal disease. Microalbuminuria, a predictor of diabetic nephropathy, was screened for in newly diagnosed diabetics with the objectives of finding its prevalence and factors associated with its development. The Micral-Test strip was used to screen for microalbuminuria in 66 newly diagnosed diabetics (21 Type 1, 45 Type 2) and 36 non-diabetic controls. Microalbuminuria was present in 50% of diabetics and 8% of controls. Compared with the control group, diabetics had a higher prevalence of smoking, significantly higher mean systolic and diastolic blood pressure and mean arterial pressure. Retinopathy was present in 23% of diabetics and was more frequently encountered in females. From multiple regression analysis smoking, systolic blood pressure, mean arterial pressure and retinopathy were significantly associated with microalbuminuria. In conclusion, microalbuminuria occurs commonly in newly diagnosed diabetics and its development is associated with elevated levels of systolic blood pressure, mean arterial pressure, retinopathy and smoking. Screening for this associated factors of diabetic nephropathy is recommended as a routine in all newly diagnosed diabetics.

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.

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.

Electrocardiographic left ventricular hypertrophy by five criteria among civil servants in Benin City, Nigeria: prevalence and correlates

Although increasing hypertension rates have been reported in several African populations, little is known about the frequency of resulting hypertensive complications in these populations. We recorded the electrocardiograms of 482 male and 284 female civil servants in Benin City, Nigeria. Five different criteria were used to detect the presence of electrocardiographic left ventricular hypertrophy. Associations between electrocardiographic left ventricular hypertrophy and demographic, anthropometric and blood pressure characteristics were assessed. The prevalence of electrocardiographic left ventricular hypertrophy ranged from 3 to 29% in the total population, depending on the criteria used, with four of the five criteria resulting in prevalence estimates of less than 10%. The prevalence of electrocardiographic left ventricular hypertrophy was significantly greater among those with hypertension (19% of the total population), ranging from 11 to 49%. The prevalence of electrocardiographic left ventricular hypertrophy increased with blood pressure level in both normotensives and hypertensives. Among hypertensives with systolic blood pressure > or =180 mm Hg or diastolic blood pressure > or =110 mm Hg, the prevalence exceeded 50% by four of the five criteria. We conclude that left ventricular hypertrophy may be affecting many hypertensives in this Nigerian population, potentially resulting in a substantial future burden of cardiovascular disease and death.

Apolipoprotein J polymorphisms and serum HDL cholesterol levels in African blacks

Apolipoprotein J (apoJ, protein; APOJ, gene) is found in serum associated with high-density lipoprotein (HDL) subfractions, which also contain apolipoprotein A-I (apoA1) and cholesteryl ester transfer protein. ApoJ has been shown to be involved in a variety of physiological functions, including lipid transport. In earlier studies we reported the existence of a common genetic polymorphism (APOJ*1 and APOJ*2 alleles) using isoelectric focusing (IEF) and immunoblotting. In this study we determined the molecular basis of this polymorphism and together with another polymorphism at codon 328 (G-->A) evaluated its relationship with serum HDL cholesterol and apoA1 levels in 767 African blacks stratified by staff level: junior (less affluent, n = 450) and senior (more affluent, n = 317). The molecular analysis of the cathodally shifted APOJ*2 allele on IEF gels revealed an amino acid substitution of asparagine by histidine resulting from a missense mutation (A-->C) at codon 317 in exon 7. The frequency of the APOJ*2 (C) allele of codon 317 in the total sample was 0.267, whereas that of the less common allele A of codon 328 was 0.04. Despite their close proximity, no linkage disequilibrium was observed between the 2 polymorphisms. The impact of the codon 317 polymorphic variation was significant on serum HDL cholesterol (p = 0.003) and HDL3 cholesterol (p = 0.001) in junior staff. The adjusted mean values of these traits were higher in the codon 317 APOJ*2/*2 genotype than in the *1/*1 and *1/*2 genotypes. Overall, the APOJ codon 317 polymorphism explained 10.2% and 8.3% of the phenotypic variation in HDL cholesterol and HDL3 cholesterol, respectively, in junior staff. The codon 328 polymorphism showed a significant effect on HDL2 cholesterol (p = 0.039) and apoA1 (p = 0.007) only in junior women and accounted for 2.5% and 4.2% of the phenotypic variation in HDL2 cholesterol and apoA1, respectively. We also analyzed the combined effects of these genotypes at the 2 polymorphic sites. Significant effects on HDL cholesterol (p = 0.004) and HDL3 cholesterol (p = 0.008) in junior men and on HDL2 cholesterol (p = 0.003) in junior women were observed in the combined genotype data. The 2-locus genotypes explained 6.0% and 5.3% of the residual phenotypic variation of HDL cholesterol and HDL3 cholesterol in junior men and 10.4% of HDL2 cholesterol in junior women. These data indicate that the effect of the APOJ polymorphism on HDL cholesterol levels is modulated by socioeconomic status, as measured by staff level. Given the association of HDL and its subfractions with cardiovascular disease, these polymorphisms may lead to a better understanding of interracial differences in the risk of cardiovascular disease.

Apolipoprotein A kringle 4 polymorphism and serum lipoprotein (a) concentrations in African blacks

Several epidemiological studies have established that elevated serum lipoprotein (a) [Lp(a)] levels are independent risk factors for coronary heart disease, stroke, and restenosis of coronary lesions in white and Asian populations. Serum Lp(a) levels vary over a 1000-fold range among individuals and are under strict genetic control. Serum Lp(a) levels are significantly higher in populations with African ancestry than in populations of European ancestry. The APOA gene exhibits hypervariable length polymorphism resulting from a variable number of expressed kringle 4 repeats. An inverse relationship exists between the size of kringle 4 repeats and serum Lp(a) levels. However, most studies have been conducted in whites, and the data are scanty in African populations. To explore this relationship among Africans, we determined serum Lp(a) levels and APOA Kringle 4 size polymorphisms in 781 unrelated Africans (490 men, 291 women) from Benin City, Nigeria. Mean and median serum Lp(a) values were 25.6 +/- 0.6 mg/dl and 20.9 mg/dl, respectively. Although there was no difference in mean Lp(a) values between men and women, median Lp(a) values were higher in women than in men (p = 0.02). Using SDS-agarose gel electrophoresis, we detected 38 APOA isoforms, the highest number recorded to data. There were 10 consecutive medium-size alleles whose frequencies ranged between 4.2% and 10.9%, and together they accounted for 72.8% of the alleles observed in this population. Spearman's correlation coefficients showed an inverse relationship between the size of the APOA isoform and Lp(a) levels using either single-banded (r = 0.46; p < 0.0001) or double-banded (r = 0.42; p < 0.0001) phenotypes. Using random effects analysis of variance on the entire sample, the APOA size polymorphism explained about 15% of the phenotypic variation in Lp(a) levels. These data suggest that despite significant correlation between the APOA kringle 4 size polymorphism and Lp(a) levels, other sequence variations either in the APOA gene or closely linked genes may account for relatively higher Lp(a) levels found in Africans.

John Henryism and blood pressure among Nigerian civil servants

STUDY OBJECTIVE

Among urban Nigerian civil servants, higher socioeconomic status is related to increased blood pressure. In the United States, the relation between increased blood pressure and low socioeconomic status or low level of education has been found to be potentiated by high effort active coping (John Henryism) among African-Americans. Thus, the potentiating effect of high effort active coping as measured by the John Henryism Active Coping Scale, on socioeconomic status, as measured by job grade, was considered in relation to blood pressure in a Nigerian civil servant population.

DESIGN

The influence of John Henryism on the association between educational level or socioeconomic status and increased blood pressure was examined during a comprehensive blood pressure survey. John Henryism refers to a strong behavioural predisposition to actively cope with psychosocial environmental stressors.

SETTING

Benin City, Nigeria.

PARTICIPANTS

Nigerian civil servant sample of 658 adults, aged 20 to 65 years.

MAIN RESULTS

Among those with high John Henryism scores of upper socioeconomic status, whether measured by education level or job grade, there was a trend toward higher systolic and diastolic blood pressures, adjusted for age and body mass index, in men and women, though not statistically significant.

CONCLUSIONS

This trend is consistent with recent findings of increased blood pressure among women and African-Americans with high John Henryism and high status jobs.

Black-white differences in hip geometry. Study of Osteoporotic Fractures Research Group

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.

Lipoprotein (a) distribution in a Nigerian population

OBJECTIVES

To determine the distribution and determinants of lipoprotein (a) (Lp(a)) concentration among Nigerians.

METHODS

Subjects were recruited from civil servants living in Benin City, Nigeria. The height and weight of the individuals were measured and their use of alcohol and tobacco estimated by questionnaire. Laboratory analyses of blood samples involved Lp(a), total cholesterol (TC), high-density lipoprotein (HDLc), HDL2c, HDL3c, triglyceride (TG) and insulin.

RESULTS

The analyses indicate that the Lp(a) concentrations are elevated among Nigerian populations and more skewed towards high levels than is observed for caucasian and oriental groups. The median levels for Lp(a) were 24.0 mg dl-1 and 19.0 mg dl-1 for women and men, respectively. This difference was significant (P < 0.05) but after stratifying by age, only the 45-54 year-old group of women (30.1 mg dl-1) had significantly higher (p < 0.001) median concentrations of Lp(a) than men (18.4 mg dl-1). Age, 20-64, had no influence on Lp(a) levels in men but in women Lp(a) concentrations increased significantly with age (p < 0.05). Among males alcohol consumption, smoking and body mass index (BMI) were not related to Lp(a) concentrations but a significant effect (p < 0.05) was noted for waist-hip ratio (WHR). Among females no relationship was observed between Lp(a) levels and alcohol consumption, BMI and WHR. All serum lipids measured (TC, HDLc, HDL2c, HDL3c, low-density lipoprotein (LDLc), and TG) were correlated with Lp(a) concentrations among men. A significant association with TC and LDLc remained after correcting for Lp(a) cholesterol. Among women, the Lp(a) levels were associated with TC, HDLc, HDL3c, and LDLc but not with HDL2c, and TG. The correlations with TC and LDLc were not significant after correcting for Lp(a) cholesterol. Insulin did not correlate with Lp(a) levels in either men or women.

CONCLUSIONS

Lp(a) concentrations are high in Nigerians, particularly among women, and the association between the Lp(a) concentrations and other lipoproteins is stronger than in white populations.

The role of socioeconomic status and serum fatty acids in the relationship between intake of animal foods and cardiovascular risk factors

Little is known regarding the relationship of serum fatty acids to cardiovascular risk factors in Nigerian populations. Civil servants with higher socioeconomic status (SES) in Nigeria appear to be in cultural transition toward a more Westernized lifestyle. For this study the food intakes of 397 civil servants were estimated from two 24-h recalls. Fatty acids in serum total lipids were measured in both absolute weight concentration and percentage composition. Daily meat intake was 43.5 g, and fish intake was 70.5 g. The intakes of meat, eggs, and milk were higher in high SES Nigerians than in low SES Nigerians. The concentration of total fatty acids (TFA, the sum of 12 serum fatty acids) was also higher in high SES men and women, as compared with low SES men and women (2064, 2060, 1831, and 1776 mg/L, respectively). There were significant direct associations between meat intake and serum level of arachidonic acid, and between fish intake and serum levels of eicosapentaenoic acid and docosahexaenoic acid. TFA was positively associated with cholesterol, low-density-lipoprotein cholesterol (LDLc), and triglycerides across gender and SES groups after adjustment for body mass index, fasting insulin level, and age. Nigerian women were compared with two groups of American women. We concluded that fatty acids in absolute weight concentration reflected the amount of fat intake. The level of TFA was directly related to cardiovascular risk factors in Nigerians. Follow-up of such populations in cultural transition can facilitate the understanding of the true roles of animal food intake in the early evolution of atherosclerosis.

Correlates of serum lipids in a lean black population

Exposure to an urban, sedentary work environment and higher socioeconomic status (SES) may stimulate adoption of Westernized lifestyles by populations in developing countries reversing the historically low risk for coronary heart disease. In a study of serum lipids in 1407 Nigerian civil servants, aged 25-54 years, we found a more atherogenic lipid profile among higher SES males and females compared with lower SES (LDL-cholesterol, 113 vs. 97 mg/dl, males, 125 vs. 114 mg/dl, females). Mean body mass index (BMI, kg/m2) in higher and lower SES was 22.6 and 21.3, respectively, males, and 24.7 and 24.4, respectively females. A strong relationship was observed between BMI and lipids although this relationship was absent among the leanest half of the population (BMI < 21.8). In multiple regression, SES and BMI were both strong and independent predictors of cholesterol. Both high and low SES consumed a typical Nigerian low fat, high carbohydrate diet, but somewhat higher meat, milk and egg intake suggested that some Westernization of the diet had occurred among the higher SES. Physical activity was lower among the higher SES. We conclude that SES related changes in lifestyle contribute to substantially higher total and LDL-cholesterol even in a generally lean population consuming a low fat diet.

Blood pressure reactivity to stress varies by hypertensive status and sex in Nigerians

Previous studies among American and European populations have demonstrated larger blood pressure responses to behavioral challenges among men and hypertensive individuals. This is the first report of cardiovascular responses to behavioral challenges in a West African population. Blood pressure and heart rate changes in mirror image tracing and speech making tasks were recorded for 787 Nigerian civil servants participating in a comprehensive blood pressure survey conducted in Benin City, Nigeria, during 1992. Similar to findings in other populations, greater task-induced increases in systolic blood pressure (SBP) and diastolic blood pressure (DBP) were present among men than women (mean values of SBP = 22.1 vs. 18.3 mmHg, p < 0.001; and DBP means = 13.3 vs. 11.2 mmHg, p < 0.0001) and among hypertensives than normotensives (SBP means = 27.6 vs. 19.2, p < 0.0001; and DBP means = 14.1 vs. 12.1 mmHg, p < 0.05). An elevated prevalence of hypertension among men of higher staff status has been found in this population; however, higher staff status was not consistently related to cardiovascular reactivity, independent of hypertensive status. Additionally, hypertensive men who had speech-induced increases of SBP > 40 mmHg had significantly greater left ventricular mass index than did those hypertensive men with smaller SBP increases (p < 0.04). This study demonstrates that measures of cardiovascular reactivity to behavioral challenges have cross-cultural application, suggesting the need for further investigations of the interrelation of hypertension, cardiovascular reactivity, and left ventricular mass.

Weight threshold and blood pressure in a lean black population

Hypertension is virtually absent in very lean rural African populations but is becoming more common in higher-weight urban African populations and is very common in predominantly obese Westernized black populations. This implies that there is a threshold above which weight is related to blood pressure. We studied urban Nigerian civil servants, a lean population in transition toward a more Westernized lifestyle. Blood pressure, fat-related measurements, fasting insulin, physical activity, alcohol intake, macronutrient intake, and electrolyte excretion were measured in 500 male and 299 female civil servants in Benin City, Nigeria, in 1992. Median body mass index (BMI) was 21.5 kg/m2 in men and 24.0 kg/m2 in women. Examination of age-adjusted mean blood pressure across quantiles of BMI in men and women suggested a threshold of 21.5 kg/m2 below which blood pressure was not correlated with BMI. Above this threshold blood pressure was correlated with BMI. Comparison of groups above and below the lower BMI threshold found that differences in blood pressure-BMI covariation were not explained by differences in alcohol intake, caloric or macronutrient intake, or electrolyte excretion. Physical activity was higher in men below the threshold. Fasting insulin and waist-hip ratio were strongly correlated with BMI even in this very lean population but neither was independently related to blood pressure. We conclude that there is a threshold below which little relationship between blood pressure and weight is observed. Above this threshold even at levels considered lean in US blacks, weight is a major determinant of blood pressure in this population of African blacks, which shares ancestry with US blacks.

Body fat distribution and other anthropometric blood pressure correlates in a Nigerian urban elderly population

Blood pressure (BP) has been reported to be more consistently correlated with body mass index (BMI) than with waist-hip ratio (WHR) in Blacks. We present the correlates of BP in a systematic sample of 152 (65.7 pc response rate) elderly urban Nigerians, with a mean age of 72.7 yrs. +/- 12.1 for males and 73.2 yrs, +/- 11.9 for females. There were 12.3 pc and 22.3 pc obesity rates in the males and females respectively, with an equivalent mean BMI of 22.8 kg/m2 and 23.4 kg/m2 and WHR of 0.97 and 0.94. Systolic blood pressure (SBP) and diastolic blood pressure (DBP) correlated with BMI, r = 0.26; p < 0.01 and r = 0.42; p < 0.001, only in females. WHR did not correlate with BP in either sex, but waist and hip measurements correlated significantly with BP in both sexes. The most important predictor of BP is BMI for females and waist measurement for men. Although smoking and alcohol were not related to BP in either sex, the data suggests that alcohol enhanced, while tobacco inhibited weight gain significantly in males, who on the whole indulged more than the females. Fasting or two hour whole blood glucose were not related to BP. The findings are in support of the adverse effects of weight on BP in the elderly. There is need to study attitudes to adult weight gain as expressed in body shape, and to use the findings in the development of weight control programmes as part of blood pressure control in the elderly.

Adequacy of a single visit for classification of hypertensive status in a Nigerian civil servant population

BACKGROUND

Concern has been expressed regarding the adequacy of classifying individuals as hypertensive based upon a single blood pressure determination and/or the average of readings taken at a single visit and the appropriateness of these determinations in cross-cultural comparisons of rates of hypertension.

METHODS

This analysis investigated the potential classification variability by comparing hypertensive status determined by 1) a single reading, 2) an average of the second and third determination at the first visit, and 3) an average of the second and third determinations obtained at each of three visits according to a standardized protocol. Kappa statistic, sensitivity and specificity were calculated to assess the agreement of hypertension classification for 804 subjects in the Health Survey in Nigerian Civil Servants, Benin City, 1992. Data were also compared to other published studies for variability in hypertension classification with repeated blood pressure determinations.

RESULTS

Good to excellent agreement was observed for the entire population between the single blood pressure determination, the average of the first visit, and the average of three visits. Sensitivity and specificity measures were also acceptable for the entire population. Further analysis by sex and staff status (a measure of socioeconomic status) found no apparent distinctions between the groups.

CONCLUSION

Contrasting the data with other published studies, conducted in both developed and developing countries, we note no greater variability in repeated blood pressure measurements, and conclude that the average of blood pressure determinations at a single visit in this working urban population is adequate for determining hypertensive status for comparisons with hypertension rates in Westernized populations.

Obesity, body fat distribution, and blood pressure in Nigerian and African-American men and women

This article describes a study that assesses body fat distribution patterns in Nigerian and African-American males and females and determines the association between body fat distribution patterns and blood pressure in young adults of differing geographical and ethnic backgrounds. The study population was comprised of 275 African Americans (92 males and 183 females) and 282 Nigerians (219 males and 63 females). The mean ages for the African-American males and females were 18.7 and 18.9 years, respectively, compared with 21 and 19.2 years for the Nigerian males and females. African Americans were more likely to be obese and overweight compared with their Nigerian counterparts. However, there were no significant differences between the two ethnic groups within gender for body fat distribution patterns based on waist-to-hip ratio. Despite being leaner, the Nigerians had higher diastolic blood pressures than the African Americans. There were no significant associations observed between blood pressure and waist-to-hip ratio for either the Nigerian or the African-American males or females, and body mass index was associated consistently with blood pressure only among the African Americans. These findings suggest that body mass index, a general indicator of obesity, is a better correlate of blood pressure than the waist-to-hip ratio among African Americans.

Sex and ethnic differences associated with urinary sodium and potassium in African-American US white and Nigerian college students

BP and urinary sodium and potassium were assessed in 183 African-American, 113 US white and 72 Nigerian college students. SBP was higher in African-American males compared with Nigerian and US white males (123.1, 117.6 and 115.7 mmHg, respectively, P < 0.05). There were no significant differences observed between African-American and white male students in overnight urinary excretion rates of sodium and potassium. In contrast, African-American females excreted more sodium (41.0 vs. 31.3 mEq per 8 hours, P < 0.01) and potassium (12.0 vs. 8.9 mEq per 8 hours, P < 0.05) compared with white females. Only among the white students was a significant sex difference observed in urinary electrolyte excretion rates, where males excreted at higher rates than females. Multiple regression models for the African-Americans revealed that potassium explained only 4% of the SBP variance. Among the US whites and Nigerians, sodium explained 4.9% and 6.8%, respectively, of the DBP variance.

Nutritional status of urban Nigerian school children relative to the NCHS reference population

The present study assessed the growth problems in an indigenous African population of Nigerian urban public school children. The study population consisted of 1390 Nigerian children (predominantly Igbo), 718 boys and 672 girls, ages 4-10 years. Compared to the National Center for Health Statistics (NCHS) reference population, the Nigerian children had an excess prevalence of both short stature and underweight. The prevalence of short stature was 14.2% for the boys and 17.4% for the girls. Approximately 20% of the children were underweight whereas less than 1% were considered overweight. These data demonstrate an excess of both acute and chronic malnutrition relative to the NCHS reference population.

A follow up study of adult nephrotic syndrome in Nigerians: outcome and predictors of endstage renal failure

Clinical data from 88 patients who presented with the nephrotic syndrome and biopsy proven glomerular disease were analysed to determine the outcome after 8 years of follow up, and to find out the influence of glomerular histology, sex, age, plasma creatinine, creatinine clearance, hypertension, 24-hour urinary protein excretion and microscopic haematuria, on the clinical course and outcome. The results showed that at the end of follow up (8 years), 13 patients (14.8%) had died from renal failure while 24 patients (27.2%) were in chronic renal failure. Persistent renal disease was still present in 29 patients (33.0%). Of the whole group (88), mortality and endstage renal failure were highest amongst patients with focal segmental glomerulosclerosis and membrano-proliferative glomerulonephritis. Male sex, hypertension, impaired plasma creatinine and creatinine clearance in patients from these two groups were associated with progression to chronic renal failure and death from uraemia. At final observation hypertension and microscopic haematuria were marked features of these two histological groups. Prognosis in minimal change nephropathy was quite good with remission occurring in 20 patients (66.6%); persistent renal disease however occurred in 8 patients (26.6%) while 1 patient died from uraemia.

The sickle gene: a marker for blood pressure?

Blood pressure patterns were studied in 224 Nigerians comprising 22 families with at least one child with sickle cell anemia (SS) and 18 families without sickle cell anemia (AA) in a community with a high frequency of the sickle trait (AS). Among the offspring (n = 162; mean age: 10.1 years), systolic blood pressure did not differ between the SS, AS, or AA groups. However, the SS group had significantly lower diastolic blood pressure than the AS or AA groups (60.6 versus 66.5 and 65.4 mm Hg, respectively; P < .01). After controlling for genotype, age, body mass index, and sex, regression analysis revealed that age was the only independent correlate of blood pressure.

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.

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.

Blood pressure in Nigerian college males

Hypertension is a major cause of morbidity and mortality in US black populations. There are however limited data available on college educated blacks in either the United States or Africa. The purpose of the present study was to examine blood pressure and its correlates in a Nigerian college population in comparison with US data. The study population comprised 211 Nigerian male college students (mean age, 20.9 years). The means and standard deviations for systolic and diastolic blood pressures among the Nigerians were 119.9 (12.6) and 73.3 (10.0) mm Hg, respectively. Weight, height, and body mass index means for the Nigerians were 133.6 pounds, 68.5 inches, and 20.1 kg/m2, respectively. Compared with US college-educated blacks, the Nigerians had higher systolic blood pressures but were leaner than their US counterparts. There was however a significant positive correlation between weight and systolic blood pressure for the Nigerians, which was similar to that observed among US college students. These data suggest that in a lean population, the Nigerian males' weight is still an important correlate of blood pressure as is seen in the US.

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.

Blood pressure and other cardiovascular disease risk factors in black adults with sickle cell trait or glucose-6-phosphate dehydrogenase deficiency

In this study, we examined the relationship of two common genetic markers in black populations, sickle cell trait and glucose-6-phosphate dehydrogenase (G-6-PD) deficiency, to cardiovascular risk factors. The subjects were Nigerian civil servants in Benin City, Nigeria. We measured blood pressure, height, weight, sickle cell hemoglobin, G-6-PD, proteinuria, microalbuminuria and fasting serum cholesterol, high-density lipoprotein cholesterol (HDL), triglycerides, apoprotein (APO) AI, and APO B. Data were collected on age, alcohol consumption, cigarette smoking, job status, and years lived in an urban area. There were 257 males (3 SS hemoglobin, 73 AS, 181 AA) and 69 females (23 AS, 46 AA). In comparing cardiovascular risk factors, males differed only in percent of smokers (31.5 in AS vs. 17.8 in AA, P less than 0.01). Among females, only high-density lipoprotein (HDL) cholesterol differed (61.5 mg/dl in AS vs. 52.4 in AA, P less than 0.01). We hypothesize that females with sickle cell trait are more likely to use oral contraceptives than nontrait females. If so, the high-estrogen oral contraceptives available in Nigeria could elevate HDL. G-6-PD deficiency status among males (52 deficient, 207 nondeficient) and females (1 deficient, 5 carriers, 65 nondeficient) was not related to any of the cardiovascular risk factors. We conclude that sickle cell hemoglobin trait and G-6-PD deficiency are not useful genetic markers for risk factors for cardiovascular disease.

Assessment of cardiovascular risk factors in Nigerian students

The present study assessed the prevalence of cardiovascular risk factors in 65 Nigerian medical students attending the University of Benin, Benin City, Nigeria. Their ages ranged from 17 to 28 years with a mean age for men of 20.9 years and for women of 18.8 years. Approximately 8% of the men and 0% of the women were current cigarette smokers, whereas alcohol use was observed in 14.6% of the men and in 0% of the women. The Nigerian men had significantly higher diastolic blood pressures than did American black and white men. Compared to American black men, the Nigerian men had considerably lower total cholesterol and triglyceride concentrations. The Nigerian women did not differ from American black women with respect to total cholesterol, but had significantly lower triglyceride concentrations.

Haematological parameters associated with priapism in Nigerian patients with homozygous sickle cell disease

Haematological indices in 23 male homozygous sickle cell disease (SCD) patients with priapism were the subject of this study. Patients with priapism showed significantly higher haemoglobin and haematocrit levels than in controls (P less than 0.0005 in both cases). Fetal haemoglobin levels were significantly higher in the control group than in SCD patients with priapism (P less than 0.0005). The implications of these findings are discussed and it is suggested that the practice of managing some of these patients conservatively by the transfusion of packed red blood cells to build up their haemoglobin and haematocrit levels needs to be reviewed critically.

Haematological factors associated with leg ulcer in sickle cell disease

Haematological factors in 42 Nigerian patients with homozygous sickle cell disease (SS) and leg ulcers was the subject of this study. The results suggest that this complication is associated with high haemoglobin and low fetal haemoglobin levels. The role of the significantly higher mean platelet count (P less than 0.05) in male patients than in controls is not clear.