Cardiovascular Anthropometry: What Is Best Suited for Large-Scale Population Screening in Sub-Saharan Africa?

Background : Body mass index (BMI) measures overweight/obesity. It, however, especially in sub-Saharan Africa (SSA), misclassifies cardiometabolic risk. Central obesity measures are superior. We therefore sought to compare BMI, waist-to-hip ratio (WHR) and abdominal height (AH) in predicting cardiovascular disease risk in sub-Saharan Africa. Methods : Subjects had blood pressures, BMI, and WHR determined. Blood pressure was taken, weight and height measured to generate BMI, and AH measured with a new locally fabricated abdominometer. The ability of the anthropometric indices in identifying abnormal individuals needing intervention was assessed with sensitivity, specificity, and area under the receiver operator characteristic curve. Results : Adults totaling 1,508 (728 M/780 F) adults were studied. For BMI, 985 (65.3%) were normal, while 375 (24.9%), consisting of 233 males and 142 females, had normal WHR. Blood pressure was normal in 525 (34.8%) and 317 (21.0%) for systolic and diastolic blood pressures, respectively. Using BMI as gold standard, sensitivity, specificity, positive, and negative predictive values for WHR in males were 80.7, 37.5, 62.5, and 19.3%, respectively. For females and in the same order, they were 62.0, 34.3, 65.7, and 38.0%. For AH, it was equal in both genders at 82.6, 39.2, 60.8, and 17.4%. By receiver operating curves comparing AH, WHR, and BMI against blood pressure detection, the area under the curve was 0.745, 0.604, and 0.554 for AH, BMI, and WHR, respectively. Conclusion : Abdominometer-derived AH has a better sensitivity and greater area under the receiver operator curve compared with BMI and WHR in this sub-Sahara African population; implying superiority as a cardiovascular anthropometric index.

Elevation of small, dense low density lipoprotein cholesterol-a possible antecedent of atherogenic lipoprotein phenotype in type 2 diabetes patients in Jos, North-Central Nigeria

Background

The global prevalence of type 2 diabetes is increasing. Dyslipidaemia is a known complication of diabetes mellitus manifesting frequently as cardiovascular diseases and stoke. Elevation of small, dense low density lipoprotein has been recognised as a component of the atherogenic lipoprotein phenotype associated with cardiovascular complications. We speculate that the elevation of this lipoprotein particle may be the antecedent of the atherogenic lipoprotein phenotype. This study therefore aims to determine the pattern of dyslipidaemia among diabetes mellitus patients in Jos, North-Central Nigeria.

Methods

One hundred and seventy-six patients with type 2 diabetes and 154 age-matched controls were studied. The patients with diabetes were regular clinic attenders and had stable glycaemic control. None were on lipid-lowering therapy. Anthropometric indices, blood pressure, and lipids (including total cholesterol, high density lipoprotein cholesterol, and triglyceride) were measured by chemical methods using the Hitachi 902 analyzer. Low density lipoprotein cholesterol was calculated using the Friedewald’s equation. Small, dense low density lipoprotein cholesterol, −sdLDL-C was measured using the precipitation method by Hirano et al. Means of the different groups were compared using EPI Info and a P-value of <0.05 was accepted as significant difference.

Results

Total cholesterol, low density lipoprotein cholesterol, triglyceride and small, dense lipoprotein cholesterol were all significantly higher in diabetes patients than controls except high density lipoprotein cholesterol. The percentage of LDL-C as sdLDL-C among the diabetes versus control group was 45% ± 17.79 v 32.0% ± 15.93. Serum sdLDL-C concentration was determined to be 1.45 ± 0.64 among diabetes patients and 0.8 ± 0.54 among control subjects. 75% of diabetes patients had hypertension and were taking blood pressure lowering medications.

Conclusion

The classical atherogenic lipoprotein phenotype was not demonstrated among subjects with type 2 diabetes mellitus in this study, but the elevation of serum small dense low density lipoprotein cholesterol in patients with sustained hypertension suggests the establishment of atherogenic complications among our diabetes patients.

Optimal Dose of Calcium for Treatment of Nutritional Rickets: A Randomized Controlled Trial

Calcium supplementation is indicated for the treatment of nutritional rickets. Our aim was to determine the optimal dose of calcium for treatment of children with rickets. Sixty-five Nigerian children with radiographically confirmed rickets were randomized to daily supplemental calcium intake of 500 mg (n = 21), 1000 mg (n = 23), or 2000 mg (n = 21). Venous blood, radiographs, and forearm areal bone density (aBMD) were obtained at baseline and at 8, 16, and 24 weeks after enrollment. The primary outcome was radiographic healing, using a 10-point radiographic severity score. The radiographic severity scores improved in all three groups, but the rate of radiographic healing (points per month) was significantly more rapid in the 1000-mg (-0.29; 95% confidence interval [CI] -0.13 to -0.45) and 2000-mg (-0.36; 95% CI -0.19 to -0.53) supplementation groups relative to the 500-mg group. The 2000-mg group did not heal more rapidly than the 1000-mg group. Of those who completed treatment for 24 weeks, 12 (67%), 20 (87%), and 14 (67%) in the 2000-mg, 1000-mg, and 500-mg groups, respectively, had achieved a radiographic score of 1.5 or less (p = 0.21). Serum alkaline phosphatase decreased and calcium increased similarly in all groups. Forearm diaphyseal aBMD improved significantly more rapidly in the 2000-mg group than in the 500-mg and 1000-mg groups (p < 0.001). Daily calcium intakes of 1000 mg or 2000 mg produced more rapid radiographic healing of rickets than 500 mg, but 2000 mg did not have greater benefit than 1000 mg. Some children require longer than 24 weeks for complete healing of nutritional rickets. © 2016 American Society for Bone and Mineral Research.

Comparison of Limestone and Ground Fish for Treatment of Nutritional Rickets in Children in Nigeria

OBJECTIVE

To determine whether children with calcium-deficiency rickets respond better to treatment with calcium as limestone or as ground fish.

STUDY DESIGN

Nigerian children with active rickets (n = 96) were randomized to receive calcium as powdered limestone (920 mg of elemental calcium) or ground fish (952 mg of elemental calcium) daily for 24 weeks. Radiographic healing was defined as achieving a score of 1.5 or less on a 10-point scale.

RESULTS

The median (range) age of enrolled children was 35 (6-151) months. Of the 88 children who completed the study, 29 (66%) in the ground fish group and 24 (55%) in the limestone group achieved the primary outcome of a radiographic score of 1.5 or less within 6 months (P = .39). The mean radiographic score improved from 6.2 ± 2.4 to 1.8 ± 2.2 in the ground fish group and from 6.3 ± 2.2 to 2.1 ± 2.4 in the limestone group (P = .68 for group comparison). In an intention to treat analysis adjusted for baseline radiographic score, age, milk calcium intake, and serum 25-hydroxyvitamin D concentration, the response to treatment did not differ between the 2 groups (P = .39). Younger age was associated with more complete radiographic healing in the adjusted model (aOR 0.74 [95% CI 0.57-0.92]). After 24 weeks of treatment, serum alkaline phosphatase had decreased, calcium and 25-hydroxyvitamin D increased, and bone mineral density increased in both groups, without significant differences between treatment groups.

CONCLUSION

In children with calcium-deficiency rickets, treatment with calcium as either ground fish or limestone for 6 months healed rickets in the majority of children.

Prevention of nutritional rickets in Nigerian children with dietary calcium supplementation

Nutritional rickets in Nigerian children usually results from dietary calcium insufficiency. Typical dietary calcium intakes in African children are about 200mg daily (approximately 20-28% of US RDAs for age). We sought to determine if rickets could be prevented with supplemental calcium or with an indigenous food rich in calcium. We enrolled Nigerian children aged 12 to 18months from three urban communities. Two communities were assigned calcium, either as calcium carbonate (400mg) or ground fish (529±109mg) daily, while children in all three communities received vitamin A (2500IU) daily as placebo. Serum markers of mineral homeostasis and forearm bone density (pDEXA) were measured and radiographs were obtained at enrollment and after 18months of supplementation. The overall prevalence of radiographic rickets at baseline was 1.2% and of vitamin D deficiency [serum 25(OH)D<12ng/ml] 5.4%. Of 647 children enrolled, 390 completed the 18-month follow-up. Rickets developed in 1, 1, and 2 children assigned to the calcium tablet, ground fish, and control groups, respectively (approximate incidence 6.4/1000 children/year between 1 and 3years of age). Children who developed rickets in the calcium-supplemented groups had less than 50% adherence. Compared with the group that received no calcium supplementation, the groups that received calcium had a greater increase in areal bone density of the distal and proximal 1/3 radius and ulna over time (P<0.04). We conclude that calcium supplementation increased areal bone density at the radius and ulna, but a larger sample size would be required to determine its effect on the incidence of rickets.

Youth, unemployment, and male gender predict mortality in AIDS patients started on HAART in Nigeria

This retrospective study identifies risk factors for mortality in a cohort of HIV-positive adult patients treated with highly active antiretroviral therapy (HAART) in Jos, Nigeria. We analyzed clinical data from a cohort of 1552 patients enrolled in a HIV/acquired immune deficiency syndrome treatment program and started on HAART between December 2004 and 30 April 2006. Death was our study endpoint. Patients were followed in the study until death, being lost to follow-up, or the end of data collection, 1 December 2006. Baseline patient characteristics were compared using Wilcoxon Rank Sum Test for continuous variables and Pearson Chi-Square test for categorical variables to determine if certain demographic factors were associated with more rapid progression to death. The Cox proportional hazard multivariate model analysis was used to find risk factors. As of 1 December 2006, a total of 104 cases progressed to death. In addition to the expected association of CD4 count less than 50 at initiation of therapy and active tuberculosis with mortality, the patient characteristics independently associated with a more rapid progression to death after initiation of HAART were male gender, age less than 30 years old, and unemployment or unknown occupation status. Future research is needed to identify the confounding variables that may be amenable to targeted interventions aimed at ameliorating these health disparities.

Early response to vitamin D2 in children with calcium deficiency rickets

OBJECTIVE

To assess the effect of vitamin D(2) administration on serum vitamin D metabolite concentrations in calcium deficiency rickets.

STUDY DESIGN

We administered vitamin D(2), 50,000 IU orally to 16 Nigerian children 15 to 48 months of age with radiographically active rickets. We measured calcium and vitamin D metabolites at baseline and at 1, 3, 7, and 14 days.

RESULTS

At baseline, ranges of serum 25-hydroxyvitamin D (25(OH)D) concentrations were 18 to 40 nmol/L (7-16 ng/mL), and 1,25-dihydroxyvitamin D (1,25-(OH)(2)D) concentrations were 290 to 790 pmol/L (120-330 pg/mL). After vitamin D administration, serum 25(OH)D and 1,25(OH)(2)D concentrations rapidly rose and peaked at 2.8 and 1.9 times the baseline values (P < .001), respectively, at 3 days. Positive correlations between 1,25(OH)(2)D and 25(OH)D were strongest at day 3 (r = 0.84, P < .001) and weakest at day 14 (r = 0.41, P = .11). The relationship of 1,25(OH)(2)D with 25(OH)D at baseline and the increase in 1,25(OH)(2)D in response to vitamin D were similar to those described in children with vitamin D deficiency. However, unlike the pattern in vitamin D deficiency, 1,25(OH)(2)D remained positively correlated with 25(OH)D after administration of vitamin D.

CONCLUSION

Dietary calcium deficiency increases the demand for 25(OH)D above that required in vitamin D deficiency to optimize 1,25(OH)(2)D concentrations. Assessment of vitamin D sufficiency in persons or communities may need to be adjusted for habitual dietary calcium intake.

Calcium absorption in Nigerian children with rickets

BACKGROUND

Nutritional rickets is common in Nigerian children and responds to calcium supplementation. Low dietary calcium intakes are also common in Nigerian children with and without rickets.

OBJECTIVE

The objective was to assess intestinal calcium absorption in Nigerian children with rickets.

DESIGN

Calcium absorption was assessed in 15 children with active rickets (2-8 y of age) and in 15 age- and sex-matched children without rickets by using a dual-tracer stable-isotope method. The children with rickets were supplemented with calcium for 6 mo; calcium absorption was reevaluated 12 mo after the baseline study. Fractional calcium absorption could be determined in 10 children with rickets and in 10 children without rickets.

RESULTS

The children with and without rickets had dietary calcium intakes of approximately 200 mg/d. Compared with the control children, the children with rickets had lower serum 25-hydroxyvitamin D and calcium concentrations and greater 1,25-dihydroxyvitamin D and parathyroid hormone concentrations. In fact, there were 15 rachitic and 15 control children in the study. Mean (+/-SD) fractional calcium absorption did not differ between those with (61 +/- 20%) and without (63 +/- 13%) rickets (P = 0.47). Calcium absorption was not associated with serum concentrations of calcium, alkaline phosphatase, 25-hydroxyvitamin D, 1,25-dihydroxyvitamin D, or parathyroid hormone. Mean fractional calcium absorption was significantly greater after (81 +/- 10%) than before (61 +/- 20%) calcium supplementation for the treatment of rickets (P = 0.035).

CONCLUSIONS

In Nigerian children with rickets, the capacity to absorb calcium is not impaired; however, fractional calcium absorption increases after the resolution of active disease. Calcium absorption may be inadequate to meet the skeletal demands of children with rickets during the active phase of the disease, despite being similar to that of control children.

Case-control study of factors associated with nutritional rickets in Nigerian children

OBJECTIVE

Because the causes of nutritional rickets in tropical countries are poorly understood, we conducted a case-control study to determine factors associated with rickets in Nigerian children.

STUDY DESIGN

We compared 123 Nigerian children who had rickets with matched control subjects. Dietary, demographic, anthropometric, and biochemical data were collected to assess factors related to calcium and vitamin D status, which might predispose children to rickets.

RESULTS

Mean (+/- SD) daily dietary calcium intake was low in both children with rickets and control children (217 +/- 88 mg and 214 +/- 77 mg, respectively; P =.64). Children with rickets had a greater proportion of first-degree relatives with a history of rickets (14.6% vs 3.1%; P <.001), a shorter mean duration of breast-feeding (16.0 vs 17.3 months; P =.041), and a delayed age of walking (14 vs 12 months; P <.001). Among children with rickets, biochemical features suggestive of calcium deficiency included hypocalcemia, extremely low calcium excretion, and elevated 1, 25-dihydroxyvitamin D and parathyroid hormone values. Median 25-hydroxyvitamin D concentrations were 32 and 50 nmol/L (13 and 20 ng/mL) in children with rickets and control children, respectively (P <.0001). Only 46 subjects with rickets (37%) had 25-hydroxyvitamin D values <30 nmol/L (12 ng/mL).

CONCLUSIONS

Vitamin D deficiency appears unlikely to be the primary etiologic factor of rickets in African children. Moreover, low dietary calcium intake alone does not account for rickets. Insufficient dietary calcium probably interacts with genetic, hormonal, and other nutritional factors to cause rickets in susceptible children.

Preliminary clinical investigation of the contraceptive efficacy and chemical pathological effects of RICOM-1013-J of Ricinus communis var minor on women volunteers

The seeds of Ricinus communis Linn, RICOM-1013-J, administered as a single oral dose of 2.3-2.5 g once per 12 months protected against pregnancy in 50 women volunteers for a period of one year. The antifertility and contraceptive efficacy of the seed was demonstrated in this study. Clinical observation revealed very minimal side effects. Some of the side effects investigated included headache, nausea, vomiting, weight gain, loss of appetite, raised blood pressure and dysmenorrhoea. Furthermore, both the renal and liver functions were not affected as revealed by urea, electrolyte and creatinine values as well as total bilirubin, conjugated bilirubin, serum albumin, total protein and transaminases values when compared with control values. In addition cholesterol and phospholipids were not significantly altered. When all these results are considered together, it seems unlikely that the antifertility and contraceptive efficacy of RICOM-1013-J is due to hormonal mechanisms alone since side effects, renal and liver function, and cholesterol effects attributable to oestrogen and/or progesterone were minimal in the volunteers.

Chemical, pathological and toxicological studies of the effects of RICOM-1013-J of Ricinus communis var minor on women volunteers and rodents

RICOM-1013-J (Ricinus communis var minor) administered orally once to each of 12 women volunteers at a dose of 2.5-2.7 g per 8 months, protected against pregnancy over a period of 7-8 months of study. A study of the effect of a contraceptive dose (20 mg/kg) on metabolic parameters in rat (food and water in-take, urine and faecal output and body weight) over a period of 4 months showed a slight decrease in all the parameters in the first 1-8 weeks. This effect was reversible attaining pretreatment levels from week 16. The LD(50) in an acute toxicity test in mice was 63.1 +/- 16.0 g/kg s.c. Determination of blood urea, sodium (Na(+)), potassium (K(+)), chloride (Cl(-)) and bicarbonate (HCO$_¿3¿ ¿-¿$)as a measure of renal function and alkaline phosphatase (ALP), transaminases (GPT and GOT) and transpeptidases (GGT) as a measure of liver function showed that liver function profiles in pretreated rats were not significantly different from control (p < 0.05) on day 21 to day 150. However, serum levels of ALP and GGT at day 120 to day 150 were moderately but significantly elevated (p > 0.05) compared with the control. There were no significant changes in renal function profiles in pretreated rats (p < 0.05) compared with the control. The results of the liver and renal function profiles in women volunteers showed that there were no significant (p < 0.05) changes in renal functions on day 206 following RICOM-1013-J administration. However, serum levels of ALP and GGT showed a slight rise in about 70% of volunteers, whereas bilirubin and transaminases levels were normal. The present results indicate a very high efficacy and margin of safety of RICOM-1013-J in women volunteers. The increase in ALP and GGT in both animal and women volunteers suggest mild intrahepatic cholestatic changes which may be attributed to an oestrogenic effect of RICOM-1013-J.

A comparison of calcium, vitamin D, or both for nutritional rickets in Nigerian children

BACKGROUND

Nutritional rickets remains prevalent in many tropical countries despite the fact that such countries have ample sunlight. Some postulate that a deficiency of dietary calcium, rather than vitamin D, is often responsible for rickets after infancy.

METHODS

We enrolled 123 Nigerian children (median age, 46 months) with rickets in a randomized, double-blind, controlled trial of 24 weeks of treatment with vitamin D (600,000 U intramuscularly at enrollment and at 12 weeks), calcium (1000 mg daily), or a combination of vitamin D and calcium. We compared the calcium intake of the children at enrollment with that of control children without rickets who were matched for sex, age, and weight. We measured serum calcium and alkaline phosphatase and used a 10-point radiographic score to assess the response to treatment at 24 weeks.

RESULTS

The daily dietary calcium intake was low in the children with rickets and the control children (median, 203 mg and 196 mg, respectively; P=0.64). Treatment produced a smaller increase in the mean (+/-SD) serum calcium concentration in the vitamin D group (from 7.8+/-0.8 mg per deciliter [2.0+/-0.2 mmol per liter] at base line to 8.3+/-0.7 mg per deciliter [2.1+/-0.2 mmol per liter] at 24 weeks) than in the calcium group (from 7.5+/-0.8 [1.9+/-0.2 mmol per liter] to 9.0+/-0.6 mg per deciliter [2.2+/-0.2 mmol per liter], P<0.001) or the combination-therapy group (from 7.7+/-1.0 [1.9+/-0.25 mmol per liter] to 9.1+/-0.6 mg per deciliter [2.3+/-0.2 mmol per liter], P<0.001). A greater proportion of children in the calcium and combination-therapy groups than in the vitamin D group reached the combined end point of a serum alkaline phosphatase concentration of 350 U per liter or less and radiographic evidence of nearly complete healing of rickets (61 percent, 58 percent, and 19 percent, respectively; P<0.001).

CONCLUSIONS

Nigerian children with rickets have a low intake of calcium and have a better response to treatment with calcium alone or in combination with vitamin D than to treatment with vitamin D alone.

Absence of vitamin D deficiency in young Nigerian children

OBJECTIVE

To determine the prevalence of vitamin D deficiency in young Nigerian children residing in an area where nutritional rickets is common.

STUDY DESIGN

A randomized cluster sample of children aged 6 to 35 months in Jos, Nigeria.

RESULTS

Of 218 children evaluated, no child in the study had a 25-hydroxyvitamin D (25-OHD) concentration <10 ng/mL (the generally held definition of vitamin D deficiency). Children spent an average of 8.3 hours per day outside of the home. Twenty children (9.2%) had clinical findings of rickets. Children with clinical signs of rickets were more likely to be not currently breast fed and have significantly lower serum calcium concentrations than those without signs of rickets (9.1 vs 9.4 mg/dL, respectively, P =.01). Yet, 25-OHD levels were not significantly different between those children with clinical signs of rickets and those without such clinical signs.

CONCLUSION

Vitamin D deficiency was not found in this population of young children in whom clinical rickets is common. This is consistent with the hypothesis that dietary calcium insufficiency, without preexisting vitamin D deficiency, accounts for the development of clinical rickets in Nigerian children.

Calcium supplements increase the serum levels of crosslinked N-telopeptides of bone collagen and parathyroid hormone in rachitic Nigerian children

OBJECTIVES

Biochemical markers of bone turnover were measured in the sera of 16 controls and 10 children with calcium-deficiency rickets, during a 12-week course of calcium supplementation (1 g CaCO3/d) that was effective in healing the bone lesions of the rachitic children.

DESIGN AND METHODS

Serum levels of crosslinked N-telopeptides of bone collagen (NTx), parathyroid hormone (PTH), alkaline phosphatase (ALP), and urinary deoxypyridinoline (LP) were assayed at baseline and during the course of calcium therapy and compared with data of the 16 non-rachitic controls.

RESULTS

Calcium therapy suppressed serum NTx and PTH levels in the rachitic children within 24 h; however, after the first week, PTH and NTx levels increased to the extent that at 12 weeks both were elevated when compared with controls or to baseline levels. Serum levels of NTx and PTH were correlated in the controls and experimental subjects (r = 0.63, p < 0.001).

CONCLUSIONS

The rate of bone resorption, as estimated by serum NTx concentration, is increased during the healing of rachitic lesions.

Serum levels of the pyridinoline crosslinked carboxyterminal telopeptide of type I collagen (ICTP) and osteocalcin in rachitic children in Nigeria

OBJECTIVES

We measured the levels of the pyridinoline crosslinked carboxyterminal telopeptide of type I collagen (ICTP) and osteocalcin (OC) in the serum of 12 rachitic and 27 healthy Nigerian children, and compared the performance of these relatively new markers of bone metabolism with established laboratory parameters of skeletal disease.

DESIGN AND METHODS

Active rickets was diagnosed on the basis of clinical and biochemical criteria. Serum calcium and phosphorus concentration and alkaline phosphatase activity were determined using clinically accepted methods. Radioimmunoassay was performed to quantify parathyroid hormone, 1-,25-dihydroxyvitamin D, OC, and ICTP.

RESULTS

The rachitic children had statistically significant serum elevations of ICTP and osteocalcin as compared with age- and sex-matched controls. Serum levels of ICTP correlated with alkaline phosphate activity.

CONCLUSIONS

As a marker of abnormal bone metabolism, ICTP performs at least as well as alkaline phosphate. ICTP and OC are valuable additions to the growing repertoire of bone markers.