Svininfluensa, lunginflammation och D-vitamin

[Svininfluensa del 14]
Det påstås att D-vitamin (egentligen är det ett hormon som bildas i huden av UV-strålning) skulle skydda mot bl.a. influensa. Finns det vetenskapliga bevis? Ja det finns i varje fall forskning som visar att D-vitamin-brist skulle kunna förvärra följderna av en infektion. Dels pekar omfattande forskning på att lunginflammation och luftvägsinflammationer är vanligare hos människor med D-vitaminbrist. Dels finns än mer omfattande forskning som visar att vitamin D har viktiga immun-reglerande och -förbättrande effekter. Slutligen finns det s.k. anekdotiska bevis (d.v.s. observationer från läkare och andra) som tyder på att D-vitaminbehandling minskar smitta.

På Vitamin D Council presenteras t.ex. två brev som organisationen fått från läkare som noterat att patienter som D-vitamin-behandlas inte utvecklat klassiska influensasymptom trots att personalen insjuknat. För att citera delar: "CWC is a long-term care facility for people with developmental disabilities, home for approx. 275 people with approx. 800 staff. Serum 25-OHD has been monitored in virtually all residents for several years and patients supplemented with vitamin D. In June, 2009, at the time of the well-publicized Wisconsin spike in H1N1 cases, 2 residents developed influenza-like illness (ILI) and had positive tests for H1N1: one was a long-term resident; the other, a child, was transferred to us with what was later proven to be H1N1. On the other hand, 60 staff members developed ILI or were documented to have H1N1... So, it is rather remarkable that only two residents of 275 developed ILI, one of which did not develop it here, while 103 of 800 staff members had ILI. It appears that the spread of H1N1 was not from staff-to-resident but from resident-to-staff (most obvious in the imported case) and between staff, implying that staff were susceptible and our residents protected."

Finns gemensamma nämnare mellan D-vitaminbrist och influensariskfaktorer? Ja det gör det. Följande är gemensamt: (sjuklig) fetma, hjärtkärlsjukdom, lungsjukdom (astma, KOL etc), lunginflammtion, immunsvarsproblem, muskelsvaghet, dålig tandhälsa (ökar risken för lunginflammation), diabetes, pre-eklampsi m.m.

En kvalificerad gissning är att s.k. "friska", men även de som blir akut sjuka, utöver eventuella andra problem, har kraftig D-vitaminbrist* (modern forskning anger mindre än 50-80 nmol/l som brist) och, som en följd av denna, en immunstörning som leder till drastiskt försämrad förmåga att bekämpa infektioner från virus och bakterier. Särskilt infektioner i lungvävnad.

En orsak till de motsägelsefulla resultaten från influensa- och vaccinstudier skulle möjligen kunna förklaras av detta. Kan du göra något? Tja, det skadar inte att äta D-vitamin i måttliga mängder (max 2000IU/d, undvik tillskott med A-vitamin/retinol då detta är toxiskt, teratogent och D-vitamin-antagonistiskt--det är av detta skäl som apoteken numera endast säljer D-droppar till barn och inte AD-droppar.)

Hur som helst krävs mera forskning innan något kan påstås med säkerhet.

*Eller avvikelser i vitamin-D-receptorn eller -metabolismen.

Andra bloggar om D-vitamin, luftvägssjukdomar, A(H1N1), svininfluensan, influensa, vaccin, H1N1, pandemi,
_________________
För länkar till d-vitamin relaterade seminarier från University of California TV se Grassroots Health.
För länkar till mera läsning och vetenskapliga artiklar kategoriserade på ämne se Vitamin D Council.
_________________
Källor i urval:
(1) On the epidemiology of influenza. John J Cannell , Michael Zasloff , Cedric F Garland , Robert Scragg and Edward Giovannucci. Virology Journal 2008, 5:29
(2) Vitamin D signaling, infectious diseases, and regulation of innate immunity. White JH. Infect Immun. 2008 Sep;76(9):3837-43. Epub 2008 May 27.
(3) Vitamin D and innate immunity. Hewison M. Curr Opin Investig Drugs. 2008 May;9(5):485-90.
(4) Unexpected actions of vitamin D: new perspectives on the regulation of innate and adaptive immunity. Adams JS, Hewison M. Nat Clin Pract Endocrinol Metab. 2008 Feb;4(2):80-90.
"...vitamin D insufficiency is a clinical problem of global proportions; secondly, epidemiology has linked vitamin D status with disease susceptibility and/or mortality; and, thirdly, expression of the machinery required to synthesize 1,25-dihydroxyvitamin D in normal human tissue seems to be much more widespread than originally thought."
(5) Control of autoimmune diseases by the vitamin D endocrine system. Adorini L, Penna G. Nat Clin Pract Rheumatol. 2008 Aug;4(8):404-12.
(6) Reversing bacteria-induced vitamin D receptor dysfunction is key to autoimmune disease. Waterhouse JC, Perez TH, Albert PJ. Ann N Y Acad Sci. 2009 Sep;1173:757-65.
"Evidence has been accumulating that indicates that a number of autoimmune diseases can be reversed by gradually restoring VDR function with the VDR agonist..."
(7) The Vitamin D Connection to Pediatric Infections and Immune Function. Walker VP, Modlin RL. Pediatr Res. 2009 Jan 28. [Epub ahead of print]
"In children, an association between nutritional rickets with respiratory compromise has long been recognized. Recent epidemiological studies clearly demonstrate the link between vitamin D deficiency and the increased incidence of respiratory infections."
(8) Vitamin D, respiratory infections, and asthma. Ginde AA, Mansbach JM, Camargo CA Jr. Curr Allergy Asthma Rep. 2009 Jan;9(1):81-7.
"Emerging evidence indicates that vitamin D-mediated innate immunity, particularly through enhanced expression of the human cathelicidin antimicrobial peptide (hCAP-18), is important in host defenses against respiratory tract pathogens. Observational studies suggest that vitamin D deficiency increases risk of respiratory infections."
(9) Vitamin D and respiratory health. Hughes DA, Norton R. Clin Exp Immunol. 2009 Oct;158(1):20-5. el. www.ncbi.nlm.nih.gov/pubmed/19737226
"Vitamin D appears capable of inhibiting pulmonary inflammatory responses while enhancing innate defence mechanisms against respiratory pathogens. Population-based studies showing an association between circulating vitamin D levels and lung function..."
"An important systemic consequence of COPD is muscle weakness, and this is associated with an increased risk of mortality. Vitamin D plays a role in influencing skeletal muscle function, with deficiency resulting in muscle weakness, and VDRs are present in this tissue [40]. It has been reported recently that polymorphisms in the VDR can influence muscle weakness in both healthy individuals and patients with COPD [41], suggesting that the VDR has a significant influence on one of the important complications of this disease."
"We have observed recently that the mean vitamin D status of patients with COPD in Norfolk, UK, is lower than that of the general population in winter and only one of 24 patients had plasma levels of 25(OH)D above 20 ng/l (unpublished)."
(10) Relationship between serum 25-hydroxyvitamin d and pulmonary function in the third national health and nutrition examination survey. Black PN, Scragg R. Chest. 2005 Dec;128(6):3792-8. el. www.ncbi.nlm.nih.gov/pubmed/16354847
"...significant association between 25-hydroxyvitamin D level and lung function after adjusting for leisure time activity and nutritional covariates. The adjusted mean difference between the highest and lowest quintile for 25-hydroxyvitamin D in this analysis was 106 mL (SE, 24 mL) for FEV1 and 142 mL (SE, 29 mL) for FVC."
(11) Vitamin D beyond bones in chronic obstructive pulmonary disease: time to act. Janssens W, Lehouck A, Carremans C, Bouillon R, Mathieu C, Decramer M. Am J Respir Crit Care Med. 2009 Apr 15;179(8):630-6. Epub 2009 Jan 22.
"In line with the novel insights on its immune function, it is tempting to speculate that vitamin D may down-regulate the inflammatory immune response in the airways while boosting innate immune defense against different microorganisms."
(12) Vitamin D and periodontal disease. Amano Y, Komiyama K, Makishima M. J Oral Sci. 2009 Mar;51(1):11-20. el. www.ncbi.nlm.nih.gov/pubmed/19325195
"...several VDR gene polymorphisms have been reported to be associated with periodontal disease. VDR ligands should prove to be useful in the treatment and prevention of periodontal disease."
(13) Role of pathogenic oral flora in postoperative pneumonia following brain surgery. Bágyi K, Haczku A, Márton I, Szabó J, Gáspár A, Andrási M, Varga I, Tóth J, Klekner A. BMC Infect Dis. 2009 Jun 29;9:104.
"The number and severity of coexisting periodontal diseases were significantly greater in patients with postoperative pneumonia in comparison to the control group (p = 0.031 and p = 0.002, respectively). The relative risk of developing postoperative pneumonia in high periodontal score patients was 3.5 greater than in patients who had low periodontal score...
(14) An association of serum vitamin D concentrations Am J Clin Nutr. 2007 Sep;86(3):714-7. el. www.ncbi.nlm.nih.gov/pubmed/17823437
(15) Association of subclinical vitamin D deficiency in newborns with acute lower respiratory infection and their mothers. Karatekin G, Kaya A, Salihoglu O, Balci H, Nuhoglu A. Eur J Clin Nutr. 2009 Apr;63(4):473-7.
"In 87.5% of all newborns and 67.5% of all mothers, serum 25(OH)D concentrations were lower than 20 ng/ml. The 25(OH)D concentrations of newborns were highly correlated with mothers' serum 25(OH)D concentrations. CONCLUSIONS: Our findings suggest that newborns with subclinical vitamin D deficiency may have an increased risk of suffering from ALRI [akut nedre luftvägsinfektion]. The strong positive correlation between newborns' and mothers' 25(OH)D concentrations shows that adequate vitamin D supplementation of mothers should be emphasized during pregnancy especially in winter months."
(16) Vitamin D status and acute lower respiratory infection in early childhood in Sylhet, Bangladesh. Roth DE, Shah R, Black RE, Baqui AH. Acta Paediatr. 2009 Nov 7. [Epub ahead of print]
"Conclusion: Vitamin D status was associated with early childhood ALRI..."
(17) Vitamin D deficiency in young children with severe acute lower respiratory infection. McNally JD, Leis K, Matheson LA, Karuananyake C, Sankaran K, Rosenberg AM. Pediatr Pulmonol. 2009 Oct;44(10):981-8.
"The mean vitamin D level for the ALRI subjects admitted to the pediatric intensive care unit (49 +/- 24 nmol/L) was significantly lower than that observed for both control (83 +/- 30 nmol/L) and ALRI subjects admitted to the general pediatrics ward (87 +/- 39 nmol/L). Vitamin D deficiency remained statistically related to pediatric intensive care unit admission in the multivariate analysis."
(18) Vitamin D deficiency and chronic lung disease. Gilbert CR, Arum SM, Smith CM. Can Respir J. 2009 May-Jun;16(3):75-80.
"Patients with chronic lung diseases such as asthma, cystic fibrosis, chronic obstructive lung disease and interstitial pneumonia appear to be at increased risk for vitamin D deficiency for reasons that are not clear. ... Various cytokines, cellular elements, oxidative stress and protease/antiprotease levels appear to affect lung fibroproliferation, remodelling and function, which may be influenced by vitamin D levels. Chronic lung diseases such as asthma and chronic obstructive lung disease have also been linked to vitamin D on a genetic basis. This immune and genetic influence of vitamin D may influence the pathogenesis of chronic lung diseases.".