Geographic location and vitamin D synthesis

Kimlin, Michael G.

doi:10.1016/j.mam.2008.08.005

Cited by 216 publications

(169 citation statements)

References 15 publications

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“…107 Ultraviolet radiation-dependent metabolism provides the major source of vitamin D in humans but at high latitudes solar radiation is too low to produce adequate levels of vitamin D, particularly in the winter. 108,109 As a result, vitamin D deficiency is associated with numerous autoimmune and infectious diseases. For instance, the worldwide distribution of reduced UVB radiation mirrors that of MS prevalence 110,111 and MS patients have significantly low circulating vitamin D levels during their adolescence compared with healthy controls.…”

Section: Environmental Factors In Mhc Class II Gene Regulationmentioning

confidence: 99%

Regulation of major histocompatibility complex class II gene expression, genetic variation and disease

et al. 2009

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Major histocompatibility complex (MHC) class II molecules are central to adaptive immune responses and maintenance of selftolerance. Since the early 1970s, the MHC class II region at chromosome 6p21 has been shown to be associated with a remarkable number of autoimmune, inflammatory and infectious diseases. Given that a full explanation for most MHC class II disease associations has not been reached through analysis of structural variation alone, in this review we examine the role of genetic variation in modulating gene expression. We describe the intricate architecture of the MHC class II regulatory system, indicating how its unique characteristics may relate to observed associations with disease. There is evidence that haplotypespecific variation involving proximal promoter sequences can alter the level of gene expression, potentially modifying the emergence and expression of key phenotypic traits. Although much emphasis has been placed on cis-regulatory elements, we also examine the role of more distant enhancer elements together with the evidence of dynamic inter-and intra-chromosomal interactions and epigenetic processes. The role of genetic variation in such mechanisms may hold profound implications for susceptibility to common disease.

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Section: Environmental Factors In Mhc Class II Gene Regulationmentioning

confidence: 99%

Regulation of major histocompatibility complex class II gene expression, genetic variation and disease

et al. 2009

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“…Therefore, populations of mid-and high-latitude countries often lack a sufficient supply with VD and have a higher risk of developing MS (Kimlin, 2008). A retrospective data analysis conducted in France showed an association between regional variation in MS prevalence and UVB radiation (Orton et al, 2011).…”

Section: Introductionmentioning

confidence: 99%

Vitamin D supplementation differentially affects seasonal multiple sclerosis disease activity

Miclea

Miclea²,

Pistor

et al. 2017

Brain and Behavior

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“…Indeed, sun exposure of hands, arms and face in non-skin-reddening doses 2-3 times/week has been suggested to satisfy the vitamin D requirement of most people (12) . Yet, decreased solar intensity makes cutaneous production unattainable from November through February at latitudes of 52°N and above (13)(14)(15) . Children living in northern latitude countries are therefore thought to be at risk of vitamin D deficiency, particularly in winter/early spring.…”

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confidence: 99%

Vitamin D status and its determinants during autumn in children at northern latitudes: a cross-sectional analysis from the optimal well-being, development and health for Danish children through a healthy New Nordic Diet (OPUS) School Meal Study

et al. 2015

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Sufficient summer/autumn vitamin D status appears important to mitigate winter nadirs at northern latitudes. We conducted a cross-sectional study to evaluate autumn vitamin D status and its determinants in 782 Danish 8-11-year-old children (55°N) using baseline data from the Optimal well-being, development and health for Danish children through a healthy New Nordic Diet (OPUS) School Meal Study, a large randomised controlled trial. Blood samples and demographic and behavioural data, including 7-d dietary recordings, objectively measured physical activity, and time spent outdoors during school hours, were collected during September-November. Mean serum 25-hydroxyvitamin D (25(OH)D) was 60·8 (SD 18·7) nmol/l. Serum 25(OH)D levels ≤50 nmol/l were found in 28·4 % of the children and 2·4 % had concentrations <25 nmol/l. Upon multivariate adjustment, increasing age (per year) (β −2·9; 95 % CI −5·1, −0·7 nmol/l), female sex (β −3·3; 95 % CI −5·9, −0·7 nmol/l), sampling in October (β −5·2; 95 % CI −10·1, −0·4 nmol/l) and November (β −13·3; 95 % CI −17·7, −9·1), and non-white ethnicity (β −5·7; 95 % CI −11·1, −0·3 nmol/l) were negatively associated with 25(OH)D (all P < 0·05). Likewise, immigrant/descendant background was negatively associated with 25(OH)D, particularly in females (β −16·3; 95 % CI −21·9, −10·7) (P < 0·001) (P interaction = 0·003). Moderate-to-vigorous physical activity (MVPA) (min/d) (β 0·06; 95 % CI 0·01, 0·12), outdoor walking during school hours (min/week) (β 0·4; 95 % CI 0·1, 0·6) and intake of vitamin D-containing supplements ≥3 d/week (β 8·7; 95 % CI 6·4, 11·0) were positively associated with 25(OH)D (all P < 0·05). The high proportion of children with vitamin D status below the recommended sufficiency level of 50 nmol/l raises concern as levels expectedly drop further during winter months. Frequent intake of vitamin D supplements was strongly associated with status. MVPA and outdoor activity during school hours should be investigated further in interventions to improve autumn vitamin D status in children at northern latitudes. Key words: Vitamin D: Children: Northern latitudes: DeterminantsDeterminants of vitamin D status are complex to evaluate but require attention as vitamin D deficiency has been found to occur commonly among, for example, healthy European children and adolescents (1) , and as vitamin D facilitates intestinal Ca absorption and optimal bone health (2,3) . Vitamin D plays a particularly crucial role during childhood growth stages, when accumulation of skeletal Ca increases vastly (4) . The vitamin D metabolite 25-hydroxyvitamin D (25(OH)D) has a half-life of 2-3 weeks, and currently serves as a suitable marker of vitamin D status (5) . Although different cut-off levels are advocated (6) , the European Society for Paediatric Gastroenterology, Hepatology and Nutrition (ESPGHAN) has recently re-established the recommendation of a 25(OH)D concentration >50 nmol/l (20 ng/ml) to indicate sufficiency (1) . Severe vitamin D deficiency during childhood, established by ESPGHAN as ...

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Geographic location and vitamin D synthesis

Cited by 216 publications

References 15 publications

Regulation of major histocompatibility complex class II gene expression, genetic variation and disease

Regulation of major histocompatibility complex class II gene expression, genetic variation and disease

Vitamin D supplementation differentially affects seasonal multiple sclerosis disease activity

Vitamin D status and its determinants during autumn in children at northern latitudes: a cross-sectional analysis from the optimal well-being, development and health for Danish children through a healthy New Nordic Diet (OPUS) School Meal Study

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