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Context: Nutritional rickets results from the interaction of low vitamin D status and limited calcium intake. Serum alkaline phosphatase (AP) activity is a biomarker of impaired mineralization in rickets.Objective: To assess the performance of serum AP activity in identifying nutritional rickets in calcium-deprived Nigerian children.Methods: We reanalyzed data from a case-control study of children with active rickets and matched control subjects without rickets, using a multivariate logistic regression to assess the odds of rickets associated with AP activity, adjusting for age, sex, and weight-for-age z-score.Results: A total of 122 children with rickets and 119 controls were included. Rachitic children had a mean (±SD) age of 54 ± 29 months, and 55 (45.1%) were male. Cases and controls had low dietary calcium intakes (216 ± 87 and 214 ± 96 mg/day, respectively). Serum AP activity levels in cases and controls were 812 ± 415 and 245 ± 78 U/L, respectively (P < 0.001). AP was negatively associated with 25-hydroxyvitamin D values (r = -0.34; P < 0.001). In the adjusted model, the odds ratio (95% CI) receiver operating characteristic curve was 0.978. AP > 350 U/L identified nutritional rickets in Nigerian children with sensitivity 0.93, specificity 0.92, positive likelihood ratio 11.3, and negative likelihood ratio 0.07.Conclusion: An AP > 350 U/L effectively discriminated between Nigerian children with and without nutritional rickets. AP is a low-cost biochemical test that could be used to screen for nutritional rickets, but cutoff values require validation in other populations, and laboratory values need to be standardized for widespread population studies. [ABSTRACT FROM AUTHOR]

Objectives African Americans (AA) have substantially lower levels of circulating 25-hydroxyvitamin D (25(OH)D) than whites. We compared population-based samples of 25(OH)D in women of African descent from Nigeria and metropolitan Chicago. Methods One hundred women of Yoruba ethnicity from southwest Nigeria and 94 African American women from metropolitan Chicago were recruited and compared using a standardized survey protocol and the same laboratory assay for 25(OH)D. Results Mean 25(OH)D levels were 64 nmol/l among the Nigerians and 29 nmol/l among the AA. Only 10% of the values were shared in common between the groups, and 76% of the Nigerians were above the currently defined threshold for adequate circulating 25(OH)D compared to 5% of the AA. Modest associations were seen between 25(OH)D and measures of obesity, although adjustment for these traits did not materially affect the group differences. Conclusion These data support the presumption that skin color is an adaptive trait which has evolved in part to regulate 25(OH)D. It remains undetermined, however, whether lower values observed in AA have negative health consequences. Am. J. Hum. Biol. 25:560-562, 2013. © 2013 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Introduction: The Western diet is associated with high consumption of processed foods preserved with phosphate. Higher dietary phosphate consumption stimulates production of fibroblast growth factor 23 (FGF23), which heightens risk for cardiovascular disease and mortality. We hypothesized that adults living in a more westernized society have higher levels of FGF23 due to increased phosphate consumption as measured by urinary phosphate excretion., Methods: We measured plasma C-terminal FGF23 levels and urinary phosphate and creatinine levels in timed urine collections among 100 African adults living in the rural area of Igbo-Ora, Nigeria (52 women, 48 men), and 100 African Americans (32 women, 68 men) living in Maywood, IL, an urban suburb of Chicago, IL, USA. Among these 200 participants, urine collections were adequate in 76 and 68 of the Maywood and Igbo-Ora participants, respectively., Results: In the total group, the mean age and body mass index, respectively, were 34.6 ± 8.2 years and 22.1 ± 3.9 kg/m(2) in Igbo-Ora, and 42.8 ± 7.2 years and 25.8 ± 6.5 kg/m(2) in Maywood. Demographic characteristics for each site were very similar after excluding participants without adequate urine collections. Among all 200 participants, the median (interquartile range) FGF23 levels were significantly higher in Maywood versus Igbo-Ora [63.8 (45.0-89.9) versus 12.5 RU/mL (8.5-18.5); P < 0.0001] and these differences did not change substantially after excluding nine women from Maywood with FGF23 levels >400 RU/mL or after excluding participants with inadequate urine collections. Among participants with adequate urine collections, the mean 24-h urinary phosphate excretion was significantly higher in Maywood versus Igbo-Ora (810.6 ± 309.0 versus 347.5 ± 153.1 mg; P < 0.001) and FGF23 levels correlated significantly with total urinary phosphate excretion (r = 0.62; P < 0.001) and urinary phosphate-to-creatinine ratios (r = 0.50; P < 0.001)., Conclusions: Living in a more westernized society may be associated with greater net phosphate absorption, as reflected by higher urinary phosphate excretion, and higher FGF23 levels., (© The Author 2014. Published by Oxford University Press on behalf of ERA-EDTA. All rights reserved.)

Background: Research in industrialized countries has demonstrated that a key factor limiting the control of hypertension is poor patient adherence and that the most successful interventions for long-term adherence employ multiple strategies. Very little data exist on this question in low-income countries, wherein medication-taking behavior may be less well developed., Method: We conducted a treatment adherence trial of 544 patients [mean age ∼63 years, mean blood pressure (BP) ∼168/92 mmHg] with previously untreated hypertension in urban and rural Nigeria. Eligible participants were randomized to one of two arms: clinic management only, or clinic management and home visits. Both interventions included three elements: a community based, nurse-led treatment program with physician backup; facilitation of clinic visits and health education; and the use of diuretics and a β blocker as needed. After initial diagnosis, the management protocol was implemented by a nurse with physician backup. Participants were evaluated monthly for 6 months., Results: Medication adherence was assessed with pill count and urine testing. Drop-out rates, by treatment group, ranged from 12 to 28%. Among participants who completed the 6-month trial, overall adherence was high (∼77% of participants took >98% of prescribed pills). Adherence did not differ by treatment arm, but was better at the rural than the urban site and among those with higher baseline BP. Hypertension control (BP <140/90 mmHg) was achieved in approximately 66% of participants at 6 months., Conclusion: This community-based intervention confirms relatively modest default rates compared with industrialized societies, and suggests that medication adherence can be high in developing world settings in clinic attenders.

Background: The relation between variation in interindividual levels of energy expenditure and weight gain remains controversial., Objective: To determine whether or not components of the energy budget predict weight change, we conducted an international comparative study in 2 cohorts of women from sociocultural environments that give rise to the extremes of obesity prevalence., Design: This was a prospective study with energy expenditure measured at baseline and weight measured annually for 3 y. Participants included 149 women from rural Nigeria and 172 African American women. The energy budget was determined by using respiratory gas exchange and doubly labeled water. Main outcomes included total, resting, and activity energy expenditure and physical activity level (ie, total energy expenditure/resting energy expenditure); baseline anthropometric measures; and annual weight change., Results: Mean body mass index (in kg/m(2)) was 23 among the Nigerians and 31 among the African Americans; the prevalences of obesity were 7% and 50%, respectively. After adjustment for body size, no differences in mean activity energy expenditure or physical activity level were observed between the 2 cohorts. In addition, in a mixed-effects, random-coefficient model, interindividual variation in activity energy expenditure at baseline was unrelated to the subsequent pattern of weight change., Conclusions: These data suggest that interindividual levels of energy expended during activity do not have a large influence on age-related trends in adiposity. In addition, contrary to expectations, these data suggest that mean activity energy expenditure does not vary substantially between contemporary social groups with low and high prevalences of obesity.

Background: Weight gain in adulthood is common, from modest gains in developing countries to substantial increases in Western societies. Evidence of the importance of energy expenditure in adult weight change has been limited to studies conducted in Pima Indians, in whom resting energy expenditure (REE) was found to be inversely associated with weight gain., Objective: The aim was to determine whether REE was predictive of weight change in lean Nigerian adults., Design: Weight was measured in 744 adults on 2-4 occasions over 5.5 y. REE was measured in the second follow-up examination. Sex-specific, mixed-effects models with REE, fat-free mass, and age as fixed effects were used to test the association between REE and weight change., Results: Adults aged >19 y (n = 352 men and 392 women) were included in these analyses. At baseline, the mean (+/-SD) age was 45.9 +/- 16.1 y for the whole population; the mean weight was 61.4 +/- 10.7 and 58.1 +/- 12.1 kg and body mass index (in kg/m(2)) was 21.4 +/- 3.2 and 23.1 +/- 4.0 for men and women, respectively. Over a mean 5.5 y of follow-up, the age-adjusted weight gain was 0.42 kg/y for the men and 0.59 kg/y for the women. In mixed-effects models, REE was positively associated with weight gain in both men and women (P < 0.001). No significant association was observed in participants who lost weight., Conclusions: In contrast with observations in overweight Pima Indians, REE adjusted for body size and composition was positively associated with weight gain in lean Nigerian adults. This suggests either that the potential for differential regulation of body weight in lean compared with overweight populations exists or that the increased REE in this population was the result, rather than cause, of weight gain.

Background: The prevalence of obesity is higher among populations in industrialized than in developing countries., Objective: We sought to compare the relations of activity energy expenditure (AEE) with adiposity and weight change in 2 black populations with different levels of obesity., Design: Total daily energy expenditure (TDEE) and resting energy expenditure (REE) were measured and AEE was calculated in 58 Nigerian and 34 US black women and men. Weight was remeasured after > or = 1 y in a subset of participants. AEE adjusted for body size and TDEE adjusted for REE were calculated with the use of the residual regression method. The cross-sectional relations between percentage body fat and activity were modeled by using regression analysis, and longitudinal relations between weight change and adjusted energy expenditure variables were calculated., Results: Women and men from the United States weighed more, had more body fat, and had higher levels of TDEE, REE, and AEE than did those from Nigeria. Cross-sectionally, AEE was negatively associated with adiposity after adjustment for body size and age (P < 0.001), regardless of site. Between 60% and 80% of the variance in adiposity was explained by AEE or TDEE. REE, AEE, and TDEE adjusted for body size and age were negatively correlated with weight change among Nigerian women but not men., Conclusions: The significant difference observed in mean adiposity between Nigerians and US blacks was not explained by differences in AEE. However, a low AEE was an important determinant of high percentages of body fat in black adults and was associated with increased weight gain in Nigerian women.