I have written in my recent editorial about the nonsense of plasma vitamin D measurements. A recent case history of a patient with a deleted vitamin D carrier molecule GC now confirms the free-hormone hypothesis. The patient’s plasma 25(OH)D levels was only 0.4% of those in the unaffected sibling.

Despite a lifelong deficiency of vitamin D binding protein, limited sun exposure (for religious reasons), and a diet that was probably lacking sufficient vitamin D, our patient did not have rickets or osteomalacia but rather osteopenia and fragility fractures that occurred in the fifth decade of life.

Another carrier sibling had only two third of the plasma 25(OH)D level compared to the unaffected sibling but showed “no appreciable clinical manifestations”.
So why measure 25(OH)D?

This is an argument that I found only recently in the excellent review  by Hellman 2017

Both humans and rodents living under laboratory conditions are generally free from worm infections, which are known to be potent inducers of IgE production. By contrast, most wild animal populations have massive amounts of intestinal worm parasites … To our knowledge, allergies have not been described in wild animals. One potential factor could be a genetic drift due to strong selection for phenotypic characteristics like coat color, long or short noses, running fast, or wanted social behaviors. Such strong selections are seen in the breeding programs for dogs, horses, and cats, but a questionable cause for human allergies. However, it is possible that we constantly need to be selecting against hypersensitivities, which may occur due to minor shift in immune functions caused by spontaneous point mutations. A strong such selection process most likely exists in wild animals under tough environmental conditions but not in domestic animals and in humans.

I agree on the observation – allergy is found only in humans and domesticated animals – while the explanation is implausible as it cannot be generalized to humans. As vitamin D supplements are both used for humans, cats, dogs, horses and lab mice, it is a more likely explanation in particular as we have now have 4 randomized trials in humans confirming the hypothesis.

We published already in 2004 that farmers use less vitamin D supplements as they spend so much time outdoors

and give their babies more raw milk avoiding supplemented milk. Just for the notes.

I have written on that before but find it striking again when reading another historical perspective.

The first insight into the possible relationship between the industrialization of Northern Europe and rickets was made by Sniadecki in 1822 when he concluded that children who lived in the inner city of Warsaw had a high incidence of rickets because of their lack of sun exposure. This was based on his clinical observations that children living in rural areas outside of Warsaw did not suffer from rickets while children born and raised in Warsaw were plagued with the disease.

Now we are supplementing vitamin D to nearly all inner city children who have a high allergy prevalence but not so much in rural areas where we see less allergy – everywhere, not only in Warsaw.

Did we trade rickets with allergy?

Unspezifische Impfeffekte  wird es wohl  geben, so der neue SPON Artikel von heute

Allerdings wird in Industrienationen daran geforscht, wie die unspezifischen Effekte früher Impfungen möglicherweise ein Leben nachwirken. Zurzeit läuft zum Beispiel eine große Studie in Australien zur Frage, ob eine frühe BCG-Impfung (gegen Tuberkulose) das Allergierisiko senkt.
Vielleicht hängt der Anstieg von Allergien ja damit zusammen, dass wir aufgehört haben, gegen Pocken und BCG zu impfen”, vermutet Aaby. Er fragt sich sogar, ob das Einstellen der Pocken-Impfung nicht auch Schaden angerichtet haben könnte, weil nun das Immuntraining durch diese Impfung ausfalle.

Der Bezug zu den Allergien ist allerdings sehr unwahrscheinlich, siehe Arnoldusson

We identified 767 articles, of which 17 satisfied our inclusion criteria; there was only 1 randomized controlled trial, with the remaining studies being epidemiologic investigations. Meta-analyses did not show any protective effect of vaccination against the risk of sensitization, as judged by specific IgE tests or skin prick testing …BCG vaccination is unlikely to be associated with protection against the risk of allergic sensitization and disease.

Es ist mir also ziemlich schleierhaft, warum das Murdoch Childrens Research Institute dazu eine Studie macht. Aber das Research Institute hat schon ganz andere Flops produziert…

Auch die Pockenimpfung schützt nicht, das ist eigentlich längst abgehakt

We found no association between having been vaccinated against smallpox in childhood and risk of atopy or allergic rhinitis. Smallpox vaccination was associated with a slightly decreased risk of asthma. There was no association between age at smallpox vaccination and risk of atopy, allergic rhinitis, or asthma. Adjusting for birth cohort, sibship size, age of the woman’s mother at birth, and social class in childhood did not change these results.

Es geht hier auch nicht so sehr um eine neue wissenschaftliche Diskussion, sondern um die journalistische Aufarbeitung eines “Dokumentarfilms”.

Nach  Masernimpfung hat im übrigen Seif Shaheen in Guinea-Bissau mehr(!) Allergien gefunden, was aber wohl auch fraglich ist, da hier nicht nur die Impfung, sondern die medizinische Betreuung generell (“iatrogen”) zur Debatte steht. Interessanterweise wird in Guinea-Bissau auch Vitamin D zur Tbc Prophylaxe gegeben wobei Vitamin D selbst ein Allergierisikofaktor ist.