Distribution analysis of vitamin D highlights differences in population subgroups: preliminary observations from a pilot study in UK adults

Abstract

There is no consensus between authors on the definition of a replete or deficient vitamin D state. Our aim was to describe a suitable method that could be used to compare vitamin D data in subject groups with small or large numbers.Two hundred and forty indigenous asymptomatic, non-pregnant adult subjects recruited from a singleconsultation outpatient attendance with normal biochemistry, represented a sample of our inner city district population. 25-hydroxyvitamin D (25,OHD 3 ) levels were measured to illustrate the effects of season, sex and ethnic group on vitamin D levels and subjected to distribution analysis. This method quantifies as a percentage the distribution of 25,OHD 3 concentrations (observed concentration, OC) in pooled group data. The data can be expressed as distribution frequency domains or cumulative frequency ogives (0-100%) or transformed into discrete linear probits, amenable to regression analysis. An estimate of the OC 50 (mid-point) and upper (either OC 75 or OC 95 ) or lower (either OC 25 or OC 5 ) range or at any other frequency between subject groups can be compared.A marked difference in 25,OHD 3 levels between Asian and non-Asian asymptomatic adult subjects was seen during both seasons. 25,OHD 3 deficiency was defined as at or below the OC 25 for the non-Asian group (for both sexes: winter <13·36 ng/ml, summer ,13·38 ng/ml). The majority of Asians of both sexes were 25,OHD 3 deficient (winter 94%, summer 82%).The distribution analysis provides an easy technique to compare 25,OHD 3 status of different subject groups, allowing the description of populations using either longitudinal or cross-sectional data. This method may offer a way of describing 25,OHD 3 deficiency between observers worldwide.

Assessment of serum 25(OH)D concentration in women of childbearing age and their preschool children in Northern Jordan during summer

“…The study was conducted during summer, and values of 25(OH)D are expected to be even lower during winter on the basis of the literature (Chapuy et al, 1996;Goswami et al, 2000;Pal et al, 2003;Pasco et al, 2004). Natural foods rich in vitamin D are not commonly consumed by the larger population, and there are no governmental regulations that (Maalouf et al, 2007), but there remain no guidelines for younger women and for children.…”

Vitamin D assessment in primary care: changing patterns of testing

“…Deficiency was reported in up to 94% of an Asian cohort in Birmingham, UK. 6 Although Liverpool does not have a large BME population, vitamin D deficiency has been noted as a health issue in its Somali community since 2003. 7,8 Consequently, the frequency of vitamin D testing is increasing, particularly in primary care.…”

Low 25(OH) vitamin D concentrations in international UK track and field athletes

“…23,24 In the UK, reduced levels of 25(OH)D have been reported in a number of studies. [25][26][27][28] A large study of postmenopausal women reported 77% of women with 25(OH)D levels <28 mcg/l. 27 Deficiencies have also been noted in 78% of patients attending a UK rheumatology clinic 26 and over 90% of an Asian cohort during a UK winter.…”

“…27 Deficiencies have also been noted in 78% of patients attending a UK rheumatology clinic 26 and over 90% of an Asian cohort during a UK winter. 25 It has been widely recognised that mean 25(OH)D levels are lower in dark-skinned individuals at all ages, with greater risk of insufficiency and deficiency. [29][30][31] This racial difference is primarily due to increased melanin pigmentation which reduces UVB absorption and subsequent vitamin D production.…”