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.

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.

Cyp17 promoter variant associated with prostate cancer aggressiveness in African Americans.

Androgens play an important role in the etiology of prostate cancer. The CYP17 gene encodes the cytochrome P450c17alpha enzyme, which is the rate-limiting enzyme in androgen biosynthesis. A T to C polymorphism in the 5' promoter region has recently been associated with prostate cancer. However, contradictory data exists concerning the risk allele. To investigate further the involvement of the CYP17 variant with prostate cancer, we typed the polymorphism in three different populations and evaluated its association with prostate cancer and clinical presentation in African Americans. We genotyped the CYP17 polymorphism in Nigerian (n = 56), European-American (n = 74), and African-American (n = 111) healthy male volunteers, along with African-American men affected with prostate cancer (n = 71), using pyrosequencing. Genotype and allele frequencies did not differ significantly across the different control populations. African-American men with the CC CYP17 genotype had an increased risk of prostate cancer (odds ratio, 2.8; 95% confidence interval, 1.0-7.4) compared with those with the TT genotype. A similar trend was observed between the homozygous variant genotype in African-American prostate cancer patients and clinical presentation. The CC genotype was significantly associated with higher grade and stage of prostate cancer (odds ratio, 7.1; 95% confidence interval, 1.4-36.1). The risk did not differ significantly by family history or age. Our results suggest that the C allele of the CYP17 polymorphism is significantly associated with increased prostate cancer risk and clinically advanced disease in African Americans.

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.

An epidemiological assessment of blood pressure determinants in an adolescent population of Nigerians.

An epidemiological assessment of blood pressure determinants in a random sample of 254 Nigerian adolescents aged 6-17 years in Benin City, Nigeria, was conducted. None of the adolescents reported cigarette smoking. Only 2.6% of the males and 0% of the females were alcohol users. Socio-economic status of the children according to parental education revealed that approximately 23% of the mothers and 9.8% of the fathers received less than a secondary (high school) education. At the other end of the education spectrum, a college education was received by 64.1% and 30.8% of the fathers and mothers, respectively. Two percent of the females and 1.3% of the males either had systolic blood pressures of greater than or equal to 140 mmHg or diastolic blood pressures of greater than or equal to 90 mmHg. No significant blood pressure differences existed between the two sexes. Among the males, it was demonstrated that age, body mass index, and heart rate were significant independent predictors of systolic blood pressure, explaining 49% of the variance. Forty-seven per cent of systolic blood pressure variance was explained by age and heart rate, for females. It was interesting to note that age was the only independent predictor of diastolic blood pressure for both males and females after control for heart rate and body mass index.

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.

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.

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.

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.

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.

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.

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.

Dietary assessment in Nigerian women: a pilot study.

A pilot study was conducted on the food consumption patterns of 67 female nursing and midwifery students attending the University of Benin Teaching Hospital, Benin City, Nigeria. The age distribution of the Nigerian students ranged from 17 to 32 years, with a mean age of 22.6 years. The Nigerians reported relatively high frequencies of consumption of beef, fish, eggs, whole milk, and palm oil. The Nigerian diet was rich in both vitamin A (yams, palm oil, spinach, tomatoes) and vitamin C (tomatoes, oranges, tangerines, mangos). This select sample of Nigerian nursing and midwifery students reported a mean caloric intake of 2540 Kcal, distributed as follows: protein 12%, carbohydrate 51%, and fat 37%. The results of this pilot indicate that the Nigerian diet is high in fat, which may put the Nigerians at increased risk for cardiovascular disease. On the other hand, the diet may be protective in terms of cancer, because of the high intake of vitamins A and C.

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.

Body fat distribution patterns and blood pressure in black and white women.

The prevalence of obesity and being overweight and the distribution of body fat in relation to blood pressure were assessed in a college population of 181 black and white US women and 124 black Nigerian women. The mean ages ranged from 18.6 to 22.4 years. Twenty-nine percent of black US women were overweight and 12.9% were obese; whereas 13.6% of white US women were overweight and 2.3% were obese. Only 18.6% of Nigerians were overweight and 1.6% were obese. More upper body fat was found among the black US women and Nigerians than among white US women. There was no significant correlation between body fat distribution and blood pressure among Nigerians. In general, among US blacks and whites, there were positive associations among body mass index, waist-hip girth measurements, and blood pressure, particularly for systolic blood pressure.

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.

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.

PIP: In 2 urban primary schools in Benin City, Nigeria, over a 3-month period, research assistants came to the classrooms of 1390 children aged 4-10 years to take anthropometric measurements so researchers could compare the nutritional status of these school children with that of a US reference population. The Nigerian school children were much shorter than the US reference population. Specifically, boys were at the 32.4 percentile and girls were at the 31.5 percentile. Further, more than 66% of the children fell in percentiles lower than the 40th percentile for height for age. 19.9 and 19.7 were the mean weight for age percentiles for boys and girls. Almost 85% of the children were below the 40th percentile of the US reference population for weight for age. More than 80% were below the 40th percentile for weight for height. 14.2% of boys and 17.4% of girls were short for their age. 19.5% of boys and 21.1% of girls were undernourished (i.e., underweight). Just less than 1% were overweight. The researchers called for further research to learn more about interpretation of growth patterns and problems between developing and developed countries, since a US reference may not be suitable for all populations.

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.