Schlagwort-Archive: vitamin-D

Cycling is good for you (and vitamin D is an activity marker)

Vitamin D level is an activity or lifestyle marker, although this has been largely neglected in the medical literature, maybe except Gannage 2000, Hyppönen 2007, Sohl 2013 and Choi 213. A new paper by de Rui in PLoS now shows that

serum 25OHD levels were significantly higher in individuals who engaged in outdoor pastimes … compared to those who did not. In particular, subjects regularly practicing gardening or cycling had higher serum 25OHD levels than those who did not, whereas 25OHD levels differed little between subjects who did or did not undertake indoor activities.

While these are good news for older cyclists Cycling is good for you (and vitamin D is an activity marker) weiterlesen

Reference values should be based on reference populations and not on politics

For a long time this has been a general rule. Just take the mean and substract two standard deviations and you get some useful reference values. Or whatever algorithm you like. This changed considerably where commercial or any other personal interests come into play. The cholesterin discussion settled only by studies showing that people with a history of cardiovascular disease may derive benefit from statins irrespective of their cholesterol levels.
I see some analogy in the vitamin D field. There is a German dermatologist who believes that 60% of all Germans are vitamin D deficient (the comments following the interview highlight this as an epiphany “totale Erleuchtung”). And a more recent paper showed that “89.9%” of all healthy newborns being insufficient. Really looks like a mix-up of some basic concepts in clinical medicine, yea, yea.

The first proven risk factor for allergy

After more than a century of research, the first successful clinical trial of an allergy risk factor has been performed. It looks like the authors even did not anticipate such an effect (known as triple blind design). But read what the Pubmed article about the Norizoe et al. paper says

To elucidate whether maternal vitamin D supplementation during lactation improves infantile eczema and other subsequent allergic disorders, a randomized, double-blind, placebo-controlled trial was performed.
Mothers (n=164) of infants with facial eczema at one-month checkup were randomly assigned to receive vitamin D3 supplements (n=82; 800 IU/day) or placebo (n=82) for 6 weeks from May 2009 to January 2011. The primary outcome was infantile eczema quantified by Scoring Atopic Dermatitis (SCORAD) index at the three-month checkup, and the secondary outcomes were atopic dermatitis, food allergy, and wheeze diagnosed by doctors up to 2 years of age.
There was no significant difference in SCORAD at 3-month checkup between two comparative groups. Doctor-diagnosed food allergy was significantly more common up to age 2 years in vitamin D group (10/39: 25.7%) than in placebo group (3/40: 7.5%; RR=3.42, 95%CI=1.02 to 11.77, P=0.030). Moreover, at least one secondary outcome was also significantly more common in vitamin D group (17/39: 43.6%) than in placebo group (7/40: 17.5%; RR=2.49, 95%CI=1.16 to 5.34, P=0.012).
These results suggest that vitamin D supplementation may not decrease the severity of infantile eczema at three months of age, but may rather increase the risk of later food allergy up to two years of age. Because a large number of subjects was lost to follow-up, further study is needed to confirm the findings.

Of course, there may be some weakness in the study design, a large loss to follow-up and the way how food allergy was diagnosed will be critized. I think, however, that this is a major breakthrough that raises the hope that we will finally understand how allergy develops.

Addendum Dec 23th, 2013

I should have added “true” risk factor, as there are positive trials on probiotics and atopic dermatitis. The meta-analysis by Lee immediately lead to a rebuttal

Their review fails to meet published standards for the quality of systematic reviews on several criteria, and this has led to inappropriate conclusions. […] These defects in methodologic rigor have led to an exaggeration of the clinical benefits of probiotics for eczema prevention.

The Cochrane Summaries are also negativ

There is not enough evidence to recommend using probiotics for the treatment of eczema.

Same situation with asthma

We found no evidence to support a protective association between perinatal use of probiotics and doctor diagnosed asthma or childhood wheeze

Why FFQs don’t predict vitamin D status

Two recent studies used food frequency questionnaires to predict vitamin D status and later allergy (Devereux 2007 and Camargo 2007) probably the only two studies that seem to contradict the vitamin D hypothesis.
New research now reported at the ATS congress [Poster Board # A84] “Measurement of Vitamin D Levels Utilizing Laboratory and Dietary Recall Information from the Tennessee Children’s Respiratory Initiative” and published in Am J Respir Crit Care Med 181;2010:A1890 shows that FFQs don’t predict vitamin D status Why FFQs don’t predict vitamin D status weiterlesen

When will they ever learn?

A new abstract shows

Perinatal data for singleton children who were prescribed anti-asthmatic medication (n = 61 256) were compared with corresponding data for all singleton children born in Sweden … (n = 1 338 319). … Being the first-born child, maternal age above 44 yr, involuntary childlessness for more than 1 yr, maternal smoking during pregnancy, maternal diabetes mellitus of any kind, pre-eclampsia, caesarean section, and instrumental vaginal delivery were all associated with an increased prescription of anti-asthmatic medication during childhood. When will they ever learn? weiterlesen

rs4711, uh rs7041

The first GWAS of human vitamin serum D level finds the most important SNPs:

In a genome-wide association study (GWAS) of 4,501 persons of European ancestry drawn from five cohorts, we identified single nucleotide polymorphisms (SNPs) in the gene encoding group-specific component (vitamin D binding) protein, GC, on chromosome 4q12-13 that were associated with 25(OH)D concentrations: rs2282679 (P=2.0 x 10–30), in LD with rs7041, a nonsynonymous SNP (D432E; P=4.1 x 10-22), and rs1155563 (P = 3.8 x 10–25).

Funny, rs7041 is the same variant rs4711, uh rs7041 weiterlesen

Close the calcium channel to get rid of allergy?

Hopefully the auto-loader at the bottom will pick some previous posts here about calcium, vitamin D and allergy; these may be necessary for the background of a new study published in the American Journal of Respiratory and Critical Care Medicine last week

We looked for Cav1 channel expression in Th2 and Th1-cells by real-time PCR and Western blotting. We sequenced the isoforms expressed by Th2-cells and tested whether Cav1 antisense oligodeoxynucleotides (Cav1AS) affected Ca2+ signaling and cytokine production […] mouse Th2 but not Th1-cells expressed Cav1.2 and Cav1.3 channels. Th2-cells transfected with Cav1AS had impaired Ca2+ signaling and cytokine production, and lost their ability to induce airway inflammation upon adoptive transfer.

This highlights again the close connection of the calcium system to immunology. While the earlier TRPM4 story was basically about mast cells, we now arrived at Th2 cells, yea, yea.

Addendum 29 April 2015

It took some time. Science has a paper on Calcium-sensing receptor antagonists abrogate airway hyperresponsiveness and inflammation in allergic asthma” by Yarova et al. writing about antagonists of the calcium-sensing receptor

We show that polycations and elevated extracellular calcium activate the human recombinant and native calcium-sensing receptor (CaSR), leading to intracellular calcium mobilization … These effects can be prevented by CaSR antagonists, termed calcilytics. Moreover, asthmatic patients and allergen- sensitized mice expressed more CaSR in ASMs than did their healthy counterparts … Thus, calcilytics may represent effective asthma therapeutics.

I don’t know, if the last statement is really warranted but – as written 5 years ago – there is a super tight connection of calcium and vitamin D to allergy.

Allergic sensitization by a food fortifier?

This week the journal “Allergy” printed a report of three cases where allergic sensitization in preterm infants is attributed to the human milk fortifier Similac.

The product contains: Nonfat milk, corn syrup solids, whey protein concentrate, and MCT oil (fractionated coconut or palm kernel oil) as sources of proteins, fat, and carbohydrate (Abbott Laboratories Pediatric Nutritional Products Guide, DIR/98A08, 2008, Mississauga, Canada).

Not listed above but in the Products Guide are 120 IU/100 ml D3 which may indeed function as a sensitizer.

Tolerogenic effects of vitamin D?

A new allergy study published last month

hypothesized that prenatal vitamin D supplementation could induce tolerogenic DC at birth. To evaluate this hypothesis in an epidemiological setting, we quantified the gene expression levels of ILT3 and ILT4 in cord blood (CB) samples of a population-based birth cohort of farm and reference children.

ILT3/IL4 as a marker of tolerogenic DCs may be justified by data published by Chang but not by newer data Tolerogenic effects of vitamin D? weiterlesen