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Rios-Leyvraz M, Thacher TD, Dabas A, Elsedfy HH, Baroncelli GI, Cashman KD. Serum 25-hydroxyvitamin D threshold and risk of rickets in young children: a systematic review and individual participant data meta-analysis to inform the development of dietary requirements for vitamin D. Eur J Nutr 2024; 63:673-695. [PMID: 38280944 PMCID: PMC10948504 DOI: 10.1007/s00394-023-03299-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Accepted: 11/28/2023] [Indexed: 01/29/2024]
Abstract
PURPOSE The objective of this systematic review was to determine a minimum serum 25-hydroxyvitamin D (25OHD) threshold based on the risk of having rickets in young children. This work was commissioned by the WHO and FAO within the framework of the update of the vitamin D requirements for children 0-3 years old. METHODS A systematic search of Embase was conducted to identify studies involving children below 4 years of age with serum 25OHD levels and radiologically confirmed rickets, without any restriction related to the geographical location or language. Study-level and individual participant data (IPD)-level random effects multi-level meta-analyses were conducted. The odds, sensitivity and specificity for rickets at different serum 25OHD thresholds were calculated for all children as well as for children with adequate calcium intakes only. RESULTS A total of 120 studies with 5412 participants were included. At the study-level, children with rickets had a mean serum 25OHD of 23 nmol/L (95% CI 19-27). At the IPD level, children with rickets had a median and mean serum 25OHD of 23 and 29 nmol/L, respectively. More than half (55%) of the children with rickets had serum 25OHD below 25 nmol/L, 62% below 30 nmol/L, and 79% below 40 nmol/L. Analysis of odds, sensitivities and specificities for nutritional rickets at different serum 25OHD thresholds suggested a minimal risk threshold of around 28 nmol/L for children with adequate calcium intakes and 40 nmol/L for children with low calcium intakes. CONCLUSION This systematic review and IPD meta-analysis suggests that from a public health perspective and to inform the development of dietary requirements for vitamin D, a minimum serum 25OHD threshold of around 28 nmol/L and above would represent a low risk of nutritional rickets for the majority of children with an adequate calcium intake.
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Affiliation(s)
- Magali Rios-Leyvraz
- Department of Nutrition and Food Safety, World Health Organization, Geneva, Switzerland.
| | - Tom D Thacher
- Department of Family Medicine, Mayo Clinic, Rochester, Minnesota, USA
| | - Aashima Dabas
- Department of Pediatrics, Maulana Azad Medical College, New Delhi, India
| | | | - Giampiero I Baroncelli
- Pediatric and Adolescent Endocrinology, Division of Pediatrics, Department of Obstetrics, Gynecology and Pediatrics, University Hospital, Pisa, Italy
| | - Kevin D Cashman
- Cork Centre for Vitamin D and Nutrition Research, School of Food and Nutritional Sciences, and Department of Medicine, University College Cork, Cork, Ireland
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Bouillon R, Antonio L. Nutritional rickets: Historic overview and plan for worldwide eradication. J Steroid Biochem Mol Biol 2020; 198:105563. [PMID: 31809867 DOI: 10.1016/j.jsbmb.2019.105563] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Revised: 11/10/2019] [Accepted: 12/02/2019] [Indexed: 02/01/2023]
Abstract
Rickets was first described in great detail in the mid 17th century and was affecting a great number of children in major European cities. The disease, however, existed already in the Roman times. The etiology of this disease remained enigmatic until the 1920s when two different mechanisms, lack of exposure to sunlight and lack of a dietary factor were finally solved by the discovery of vitamin D and its dual origin. Soon thereafter, the implementation of vitamin D supplementation for all infants and small children largely eliminated nutritional rickets in Europe and North America. It took nearly a century to elucidate the complex chemistry, metabolism, mode and spectrum of activity of the vitamin D endocrine system. Nutritional rickets, whether due to simple vitamin D or calcium deficiency or both, remains widely ravaging many infants and children around the world. Asian countries and the Middle East are mainly confronted with vitamin D deficiency whereas many African and some Asian countries face calcium deficiency rickets. Immigrants and refugees or in general people with a darker skin living in moderate climate zone are also confronted with this disease. There is great consensus how this disease could be prevented or cured. In collaboration with most international professional societies, we prepare a memorandum, in line with the successful battle against iodine deficiency disorders, to convince the World Health Organization and its member states to start an implementation program to eradicate nutritional rickets by 2030.
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Affiliation(s)
- Roger Bouillon
- Laboratory of Clinical and Experimental Endocrinology, Department of Chronic Diseases, Metabolism and Ageing, KU, Leuven, Belgium.
| | - Leen Antonio
- Laboratory of Clinical and Experimental Endocrinology, Department of Chronic Diseases, Metabolism and Ageing, KU, Leuven, Belgium
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Schnitzler CM, Pettifor JM. Calcium Deficiency Rickets in African Adolescents: Cortical Bone Histomorphometry. JBMR Plus 2019; 3:e10169. [PMID: 31346567 PMCID: PMC6636774 DOI: 10.1002/jbm4.10169] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/01/2018] [Revised: 12/11/2018] [Accepted: 12/26/2018] [Indexed: 11/24/2022] Open
Abstract
Rickets due to dietary calcium deficiency has been well described in black African children, but less is known about this condition in black adolescents. We investigated 26 black adolescents (19 males aged 11 to 19 years and 7 females aged 12 to 15 years) with rachitic leg deformities and 20 controls by routine iliac crest undecalcified cortical bone histomorphometry for disturbances of bone turnover and for mineralization defects, including severity of osteocytic osteolysis (Ot.Olysis) and periosteocytic osteolysis (Peri.Ot.Olysis) of the lacunar‐canalicular space. Serum levels of calcium (sCa), 25‐hydroxyvitamin D (25OHD), 1,25‐dihydroxyvitamin D (1,25(OH)2D), and total alkaline phosphatase (ALP) were measured. Histomorphometry showed varying degrees of severity of secondary hyperparathyroidism (20 HPT) characterized by hyperosteoidosis, increased erosion, and porosis. Because osteoid was neither being mineralized nor eroded (osteoclasts cannot erode osteoid), it increasingly blocked bone surface needed for osteoclastic resorption. Where osteoid covered >50% of bone surface, osteoid thickness, severity of Ot.Olysis, and extent of Peri.Ot.Olysis increased, sCa and 25OHD declined, and 1,25(OH)2D and ALP increased. At 80% osteoid cover, bone remodeling had all but ceased, secondary HPT had changed to osteomalacia, and serum biochemical results had deteriorated further. Disease severity was greater in males than in females, likely because males grow faster and for longer than females. In conclusion, this cross‐sectional clinical case study presents cortical bone histomorphometric data of secondary HPT and its transition to osteomalacia in black adolescents with rickets attributable to dietary calcium deficiency. The bone disease was most severe in older adolescent males. Importantly, bone pathology of calcium deficiency rickets in adolescents was not confined to bone surfaces but also manifested at osteocyte level as Ot.Olysis and Peri.Ot.Olysis. © 2019 The Authors. JBMR Plus published by Wiley Periodicals, Inc. on behalf of American Society for Bone and Mineral Research.
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Affiliation(s)
- Christine M Schnitzler
- MRC/Wits Developmental Pathways for Health Research Unit Department of Paediatrics University of the Witwatersrand Johannesburg South Africa
| | - John M Pettifor
- MRC/Wits Developmental Pathways for Health Research Unit Department of Paediatrics University of the Witwatersrand Johannesburg South Africa
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Abstract
Rickets is a bone disease associated with abnormal serum calcium and phosphate levels. The clinical presentation is heterogeneous and depends on the age of onset and pathogenesis but includes bowing deformities of the legs, short stature and widening of joints. The disorder can be caused by nutritional deficiencies or genetic defects. Mutations in genes encoding proteins involved in vitamin D metabolism or action, fibroblast growth factor 23 (FGF23) production or degradation, renal phosphate handling or bone mineralization have been identified. The prevalence of nutritional rickets has substantially declined compared with the prevalence 200 years ago, but the condition has been re-emerging even in some well-resourced countries; prematurely born infants or breastfed infants who have dark skin types are particularly at risk. Diagnosis is usually established by medical history, physical examination, biochemical tests and radiography. Prevention is possible only for nutritional rickets and includes supplementation or food fortification with calcium and vitamin D either alone or in combination with sunlight exposure. Treatment of typical nutritional rickets includes calcium and/or vitamin D supplementation, although instances infrequently occur in which phosphate repletion may be necessary. Management of heritable types of rickets associated with defects in vitamin D metabolism or activation involves the administration of vitamin D metabolites. Oral phosphate supplementation is usually indicated for FGF23-independent phosphopenic rickets, whereas the conventional treatment of FGF23-dependent types of rickets includes a combination of phosphate and activated vitamin D; an anti-FGF23 antibody has shown promising results and is under further study.
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Trilok-Kumar G, Kaur M, Rehman AM, Arora H, Rajput MM, Chugh R, Kurpad A, Sachdev HS, Filteau S. Effects of vitamin D supplementation in infancy on growth, bone parameters, body composition and gross motor development at age 3-6 years: follow-up of a randomized controlled trial. Int J Epidemiol 2015; 44:894-905. [PMID: 26130740 DOI: 10.1093/ije/dyv116] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND The long-term effects of infant vitamin D supplementation and status are unclear since there have been few controlled intervention trials and these have been small and contradictory. The Delhi Infant Vitamin D Supplementation (DIVIDS) trial found that supplementation of low-birthweight term infants with one recommended dietary allowance of vitamin D from 1 week to 6 months of age resulted in increased length and weight at 6 months. In the DIVIDS-2 study we followed up the DIVIDS children, now aged 3-6 years, to determine longer-term effects. METHODS DIVIDS children, 446 from the vitamin D arm and 466 from the placebo arm, attended the follow-up visit. Data collection included anthropometry, blood pressure, bone structure and strength by quantitative ultrasound (QUS), gross motor tests, deuterium dilution test of body composition on a subset (n = 229) and blood samples for measurement of vitamin D status. RESULTS Body mass index Z scores (BMIZ) were lower (adjusted P = 0.003)in the vitamin D Group [-1.18 (SD 0.92)] when compared with the placebo [-1.02 (SD 0.91)] group as a result of slightly lower weight and slightly greater height. The vitamin D group also had lower thigh circumference and arm muscle area and borderline lower mid-upper arm circumference. There were no group differences in body fat percentage, bone QUS or blood pressure and few differences in motor development measures. CONCLUSIONS Vitamin D supplementation of low-birthweight infants in infancy resulted in children being thinner at age 3-6 years but in no differences in functional outcomes.
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Affiliation(s)
| | - Manpreet Kaur
- Institute of Home Economics, Delhi University, Delhi, India
| | | | - Harsh Arora
- Institute of Home Economics, Delhi University, Delhi, India, Amity Institute of Biotechnology, Amity University, Noida, India
| | | | - Reema Chugh
- Institute of Home Economics, Delhi University, Delhi, India
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Dayod M, Tyerman SD, Leigh RA, Gilliham M. Calcium storage in plants and the implications for calcium biofortification. PROTOPLASMA 2010; 247:215-31. [PMID: 20658253 DOI: 10.1007/s00709-010-0182-0] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2010] [Accepted: 07/06/2010] [Indexed: 05/20/2023]
Abstract
Calcium (Ca) is an essential nutrient for plants and animals, with key structural and signalling roles, and its deficiency in plants can result in poor biotic and abiotic stress tolerance, reduced crop quality and yield. Likewise, low Ca intake in humans has been linked to various diseases (e.g. rickets, osteoporosis, hypertension and colorectal cancer) which can threaten quality of life and have major economic costs. Biofortification of various food crops with Ca has been suggested as a good method to enhance human intake of Ca and is advocated as an economically and environmentally advantageous strategy. Efforts to enhance Ca content of crops via transgenic means have had promising results. Overall Ca content of transgenic plants has been increased but in some cases adverse affects on plant function have been observed. This suggests that a better understanding of how Ca ions (Ca(2+)) are stored and transported through plants is required to maximise the effectiveness of future approaches.
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Affiliation(s)
- Maclin Dayod
- Waite Research Institute, School of Agriculture, Food and Wine, University of Adelaide, PMB1, Glen Osmond, SA 5064, Australia
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Thacher TD, Abrams SA. Relationship of calcium absorption with 25(OH)D and calcium intake in children with rickets. Nutr Rev 2010; 68:682-8. [PMID: 20961298 DOI: 10.1111/j.1753-4887.2010.00338.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Nutritional rickets has long been considered a disease caused by vitamin D deficiency, but recent data indicate that inadequate dietary calcium intake is an important cause of rickets, particularly in tropical countries. Children with rickets due to calcium deficiency do not have very low 25(OH)D concentrations, and serum 1,25(OH)(2) D values are markedly elevated. Studies of Nigerian children with rickets demonstrated they have high fractional calcium absorption. A high-phytate diet was demonstrated to increase calcium absorption compared with the fasting state, and enzymatic dephytinization did not significantly improve calcium absorption. When given vitamin D, children with rickets have a marked increase in 1,25(OH)(2) D concentrations without any change in fractional calcium absorption. No positive relationship was found between fractional calcium absorption and serum 25(OH)D concentrations in children on low-calcium diets. More research is needed to understand the interaction between calcium and vitamin D and the role of vitamin D in calcium absorption.
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Affiliation(s)
- Tom D Thacher
- Department of Family Medicine, Mayo Clinic, Rochester, Minnesota 55905, USA.
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Booher CM, Hood WR. Calcium utilization during reproduction in big brown bats (Eptesicus fuscus). J Mammal 2010. [DOI: 10.1644/09-mamm-a-186.1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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Abrams SA. Calcium absorption in infants and small children: methods of determination and recent findings. Nutrients 2010; 2:474-80. [PMID: 22254034 PMCID: PMC3257657 DOI: 10.3390/nu2040474] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2010] [Revised: 03/22/2010] [Accepted: 04/02/2010] [Indexed: 11/16/2022] Open
Abstract
Determining calcium bioavailability is important in establishing dietary calcium requirements. In infants and small children, previously conducted mass balance studies have largely been replaced by stable isotope-based studies. The ability to assess calcium absorption using a relatively short 24-hour urine collection without the need for multiple blood samples or fecal collections is a major advantage to this technique. The results of these studies have demonstrated relatively small differences in calcium absorption efficiency between human milk and currently available cow milk-based infant formulas. In older children with a calcium intake typical of Western diets, calcium absorption is adequate to meet bone mineral accretion requirements.
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Affiliation(s)
- Steven A Abrams
- Department of Agriculture, Agricultural Research Service, Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine and Texas Children's Hospital, Houston, Texas 77030, USA.
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Thacher TD, Obadofin MO, O'Brien KO, Abrams SA. The effect of vitamin D2 and vitamin D3 on intestinal calcium absorption in Nigerian children with rickets. J Clin Endocrinol Metab 2009; 94:3314-21. [PMID: 19567516 PMCID: PMC2741710 DOI: 10.1210/jc.2009-0018] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
CONTEXT Children with calcium-deficiency rickets have high 1,25-dihydroxyvitamin D values. OBJECTIVE The objective of the study was to determine whether vitamin D increased calcium absorption. DESIGN This was an experimental study. SETTING The study was conducted at a teaching hospital. PARTICIPANTS Participants included 17 children with nutritional rickets. INTERVENTION The participants were randomized to 1.25 mg oral vitamin D(3) (n = 8) or vitamin D(2) (n = 9). MAIN OUTCOME MEASURE Fractional calcium absorption 3 da after vitamin D administration was measured. RESULTS Mean baseline 25-hydroxyvitamin D concentrations were 20 ng/ml (range 5-31 ng/ml). The increase in 25-hydroxyvitamin D was equivalent after vitamin D(3) (29 +/- 10 ng/ml) or vitamin D(2) (29 +/- 17 ng/ml). Mean 1,25-dihydroxyvitamin D values increased from 143 +/- 76 pg/ml to 243 +/- 102 pg/ml (P = 0.001), and the increase in 1,25-dihydroxyvitamin D did not differ between vitamin D(2) and vitamin D(3) (107 +/- 110 and 91 +/- 102 ng/ml, respectively). The increment in 1,25-dihydroxyvitamin D was explained almost entirely by the baseline 25-hydroxyvitamin D concentration (r(2) = 0.72; P < 0.001). Mean fractional calcium absorption did not differ before (52.6 +/- 21.4%) or after (53.2 +/- 23.5%) vitamin D, and effects of vitamin D(2) and vitamin D(3) on calcium absorption were not significantly different. Fractional calcium absorption was not closely related to concentrations of 25-hydroxyvitamin D (r = 0.01, P = 0.93) or 1,25-dihydroxyvitamin D (r = 0.21, P = 0.24). The effect of vitamin D on calcium absorption did not vary with baseline 25-hydroxyvitamin D values or with the absolute increase in 25-hydroxyvitamin D or 1,25-dihydroxyvitamin D values. CONCLUSIONS Despite similar increases in 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D with vitamin D(2) or vitamin D(3), fractional calcium absorption did not increase, indicating that rickets in Nigerian children is not primarily due to vitamin D-deficient calcium malabsorption.
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Affiliation(s)
- Tom D Thacher
- Department of Family Medicine, Mayo Clinic, 200 First Street SW, Rochester, Minnesota 55905, USA.
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Abrams SA, Hicks PD, Hawthorne KM. Higher serum 25-hydroxyvitamin D levels in school-age children are inconsistently associated with increased calcium absorption. J Clin Endocrinol Metab 2009; 94:2421-7. [PMID: 19383779 PMCID: PMC2708956 DOI: 10.1210/jc.2008-2587] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CONTEXT Increasing serum 25-hydroxyvitamin D (25-OHD) in adults may enhance calcium absorption (Ca-abs). There are few similar pediatric data leading to uncertainty about the optimal target for 25-OHD to maximize Ca-abs. OBJECTIVE Our objective was to evaluate the relationship between 25-OHD and Ca-abs in a large cohort of school-age children and adolescents. DESIGN We evaluated data from 439 Ca-abs measurements performed using dual-tracer stable isotope techniques conducted at our center over a 15-yr period in 251 healthy children, 4.9-16.7 yr of age. RESULTS Serum 25-OHD ranged from 28 to 197 nmol/liter (mean 85 +/- 2 nmol/liter) (sem). Total Ca-abs (intake times fractional absorption) were significantly correlated to 25-OHD in the whole population (r = 0.16, P = 0.001). This relationship was closer in the 197 studies in early puberty (Tanner 2 or 3, r = 0.35, P < 0.001) and not significant in pre- or late pubertal subjects. For the whole population, fractional Ca-abs adjusted for calcium intake were slightly but significantly higher at 25-OHD of 28-50 nmol/liter (0.344 +/- 0.019) compared with 25-OHD of 50-80 nmol/liter (0.280 +/- 0.014) or 25-OHD greater than 80 nmol/liter (0.297 +/- 0.015, P < 0.01 for each), suggesting adaptation to moderately low 25-OHD values. CONCLUSION There is no consistent pattern of relationship between 25-OHD and either fractional or total calcium absorption in school-age children. However, there appears to be a modest calcium absorptive response to higher 25-OHD during early puberty.
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Affiliation(s)
- Steven A Abrams
- United States Department of Agriculture/Agricultural Research Service, Children's Nutrition Research Center, Houston, Texas 77030, USA.
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Thacher TD, Aliu O, Griffin IJ, Pam SD, O'Brien KO, Imade GE, Abrams SA. Meals and dephytinization affect calcium and zinc absorption in Nigerian children with rickets. J Nutr 2009; 139:926-32. [PMID: 19321589 PMCID: PMC2714392 DOI: 10.3945/jn.108.101030] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Nutritional rickets resulting from calcium insufficiency is common in Nigeria and high dietary phytate is thought to inhibit calcium and zinc absorption. We compared the effects of a high-phytate meal and enzymatic dephytinization on calcium and zinc absorption in Nigerian children with and without rickets. Nineteen children with rickets and 15 age-matched control children, aged 2-10 y, were given calcium (600 mg/d) and ergocalciferol (1250 microg/wk). After 6 wk, calcium and zinc absorption were measured in both groups with and without maize porridge using stable isotopes. One week later, absorption measurements were repeated to assess the effects of enzymatic dephytinization and fermentation of the maize porridge. The phytate concentration of maize porridge (3.87 +/- 0.38 g/kg wet weight) was reduced by enzymatic dephytinization (2.83 +/- 0.41 g/kg; P < 0.001) but not by fermentation (3.35 +/- 0.27 g/kg; P = 0.08). Calcium and zinc absorption were unaffected by the presence of rickets or by fermentation of maize porridge. Calcium absorption was greater with a meal (61.3 +/- 25.1%) than without (27.8 +/- 14.6%; P < 0.001). Zinc absorption was lower with a meal (16.2 +/- 8.0%) than without (63.4 +/- 23.9%; P < 0.001). Enzymatic dephytinization increased relative zinc absorption from a meal by 101 +/- 81% (P < 0.001) but did not affect calcium absorption. Rickets was not associated with impaired calcium or zinc absorption. Calcium absorption was enhanced by maize porridge, but zinc absorption was reduced. Enzymatic dephytinization increased zinc absorption. Multiple strategies may be required to optimize calcium and zinc absorption in deficient populations.
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Affiliation(s)
- Tom D. Thacher
- Department of Family Medicine, Mayo Clinic, Rochester, MN 55903; USDA/Agricultural Research Service Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine and Texas Children's Hospital, Houston, TX 77030; Department of Paediatrics, Jos University Teaching Hospital, Jos, Nigeria 930001; Division of Nutritional Sciences, Cornell University, Ithaca, NY 14853; and Department of Obstetrics and Gynaecology, University of Jos, Jos, Nigeria 930001
| | - Oluseyi Aliu
- Department of Family Medicine, Mayo Clinic, Rochester, MN 55903; USDA/Agricultural Research Service Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine and Texas Children's Hospital, Houston, TX 77030; Department of Paediatrics, Jos University Teaching Hospital, Jos, Nigeria 930001; Division of Nutritional Sciences, Cornell University, Ithaca, NY 14853; and Department of Obstetrics and Gynaecology, University of Jos, Jos, Nigeria 930001
| | - Ian J. Griffin
- Department of Family Medicine, Mayo Clinic, Rochester, MN 55903; USDA/Agricultural Research Service Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine and Texas Children's Hospital, Houston, TX 77030; Department of Paediatrics, Jos University Teaching Hospital, Jos, Nigeria 930001; Division of Nutritional Sciences, Cornell University, Ithaca, NY 14853; and Department of Obstetrics and Gynaecology, University of Jos, Jos, Nigeria 930001
| | - Sunday D. Pam
- Department of Family Medicine, Mayo Clinic, Rochester, MN 55903; USDA/Agricultural Research Service Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine and Texas Children's Hospital, Houston, TX 77030; Department of Paediatrics, Jos University Teaching Hospital, Jos, Nigeria 930001; Division of Nutritional Sciences, Cornell University, Ithaca, NY 14853; and Department of Obstetrics and Gynaecology, University of Jos, Jos, Nigeria 930001
| | - Kimberly O. O'Brien
- Department of Family Medicine, Mayo Clinic, Rochester, MN 55903; USDA/Agricultural Research Service Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine and Texas Children's Hospital, Houston, TX 77030; Department of Paediatrics, Jos University Teaching Hospital, Jos, Nigeria 930001; Division of Nutritional Sciences, Cornell University, Ithaca, NY 14853; and Department of Obstetrics and Gynaecology, University of Jos, Jos, Nigeria 930001
| | - Godwin E. Imade
- Department of Family Medicine, Mayo Clinic, Rochester, MN 55903; USDA/Agricultural Research Service Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine and Texas Children's Hospital, Houston, TX 77030; Department of Paediatrics, Jos University Teaching Hospital, Jos, Nigeria 930001; Division of Nutritional Sciences, Cornell University, Ithaca, NY 14853; and Department of Obstetrics and Gynaecology, University of Jos, Jos, Nigeria 930001
| | - Steven A. Abrams
- Department of Family Medicine, Mayo Clinic, Rochester, MN 55903; USDA/Agricultural Research Service Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine and Texas Children's Hospital, Houston, TX 77030; Department of Paediatrics, Jos University Teaching Hospital, Jos, Nigeria 930001; Division of Nutritional Sciences, Cornell University, Ithaca, NY 14853; and Department of Obstetrics and Gynaecology, University of Jos, Jos, Nigeria 930001
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Abstract
Africa is heterogeneous in latitude, geography, climate, food availability, religious and cultural practices, and skin pigmentation. It is expected, therefore, that prevalence of vitamin D deficiency varies widely, in line with influences on skin exposure to UVB sunshine. Furthermore, low calcium intakes and heavy burden of infectious disease common in many countries may increase vitamin D utilization and turnover. Studies of plasma 25OHD concentration indicate a spectrum from clinical deficiency to values at the high end of the physiological range; however, data are limited. Representative studies of status in different countries, using comparable analytical techniques, and of relationships between vitamin D status and risk of infectious and chronic diseases relevant to the African context are needed. Public health measures to secure vitamin D adequacy cannot encompass the whole continent and need to be developed locally.
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