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Providing perspectives on recent research into vitamins and nutritionals


Using High-Resolution Maps to Address Nutritional Gaps

By Michael McBurney

Yesterday’s blog was derived out of frustration that a health professional would undermine trust of professional colleagues and council against well-accepted recommendations in a news broadcast. Today we cover the opposite spectrum – a sensible, thought-provoking, rational recommendation to help reduce the risk of poor health in millions of people because of vitamin D insufficiency. Hats off to authors Karras, Anagnostis, Paschou, Kandaraki and Goulis.

Low vitamin D status during pregnancy is associated with many adverse health effects in the baby, including being born small for gestational age and having a lower birth weight whereas pregnant women are at increased risk of gestational diabetes, pre-eclampsia, and bacterial vaginosis. Babies born from mothers with serum 25(OH)D3 concentrations < 37.5 nmol/L weigh, on average, 46 g less and have a 0.13 cm smaller head circumference (vs mothers  ≥ 37.5 nmol/L).

Vitamin D is synthesized in skin exposed to sunshine. Skin pigmentation affects vitamin D status along with local climatic factors – outdoor temperatures, amount of sunshine, and air pollution. Karras and colleagues propose integrating geospatial data with serum 25(OH)D3 status measurements so ‘heat maps’ of vitamin D status can be created. While the vitamin D map created by the International Osteoporosis Foundation provides data at a national level, higher resolution maps integrating local factors would be useful. Climatic differences among regions in the average hours of sunshine, temperature, air pollution levels, etc. create heterogeneity within a country. Living in a tropical country with abundant sunshine does not guarantee adequate vitamin D status during pregnancy. Some communities, e.g. urban, may be more dependent upon dietary sources because they spend more time indoors than their rural counterparts.

Typically, nutrition intakes are evaluated using nationally representative dietary surveys, i.e. the National Health and Nutrition Examination Survey (NHANES 2011-2012) with 9,338 responses (out of >320,532,000 people), and to lesser extent nutritional status is assessed using biochemical measurements, i.e. CDC’s Second Nutrition Report. In almost all cases, the data, e.g. NHANES, is condensed into mean values with confidence intervals. NHANES data is nationally representative (age, sex, ethnics/race) but it is important to remember it is collected from only ~30 counties in the US. According to Wikipedia, there are 3,143 counties and county equivalents in the US. I don’t know which counties but 30 is not many. Should we expect someone living in Massachusetts, Iowa, or Oregon to have the same vitamin D status as someone living in southern California, Texas, or Florida?

With higher resolution vitamin D maps, region-specific activities can be initiated by governments, non-government organizations and businesses to better meet the vitamin D requirements of people within communities. The creation of nutrition status maps would also identify regions where serum 25(OH)D3 data has never been collected.

Thank you Dr Karras and colleagues for a great concept. Wouldn’t it be wonderful to see serum 25-hydroxyvitamin D, and other vitamin status markers, mapped using geospatial coordinates?

Main Citation

Karras SN, Anagnostis P, Paschou SA, Kandaraki E, Goulis DG. Vitamin D status during pregnancy: time for a more unified approach beyond borders? 2015 EJCN doi: 10.1038/ejcn.2015.33

Other Citations

Aghajafari F, Nagulesapillai T, Ronksley PE, Tough SC, O’Beirne M, Rabi DM. Association between maternal serum 25-hydroxyvitamin D level and pregnancy and neonatal outcomes: systematic review and meta-analysis of observational studies. 2013 BMJ doi: 10.1136/bmj.f1169

Gernand AD, Simhan HN, Klebanoff MA, Bodnar LM. Maternal serum 25-hydroxyvitamin D and measures of newborn and placental weight in a US multicenter cohort study. 2013 J Clin Endocrinol Metab doi: 10.1210/jc.2012-3275

Sachan A, Gupta R, Das V, Agarwal A, Awasthi PK, Bhatia V. Higher prevalence of vitamin D deficiency among pregnant women and their newborns in northern India. 2005 Am J Clin Nutr 81(5):1060-1064

Goswami R, Kochupillai N, Gupta N, Goswami D, Singh N, Dudha A. Presence of 25(OH)D deficiency in a rural north Indian village despite abundant sunshine. 2009 JAPI 56:755-757