Vitamin D supplementation did not prevent influenza-like illness as diagnosed retrospectively by questionnaires in subjects participating in randomized clinical trials

TY - JOUR

T1 - Vitamin D supplementation did not prevent influenza-like illness as diagnosed retrospectively by questionnaires in subjects participating in randomized clinical trials

A1 - Jorde,Rolf

A1 - Witham,Miles

A1 - Janssens,Wim

A1 - Rolighed,Lars

A1 - Borchhardt,Kyra

A1 - de Boer,Ian H.

A1 - Grimnes,Guri

A1 - Hutchinson,Moira S.

AU - Jorde,Rolf

AU - Witham,Miles

AU - Janssens,Wim

AU - Rolighed,Lars

AU - Borchhardt,Kyra

AU - de Boer,Ian H.

AU - Grimnes,Guri

AU - Hutchinson,Moira S.

PY - 2012/2

Y1 - 2012/2

N2 - <p>Background: Vitamin D deficiency has been associated with a number of diseases, including influenza. Whether or not this reflects a causal relationship is unknown. We therefore wanted to examine if supplementation with vitamin D would affect the incidence and severity of influenza-like disease. Methods: Questionnaires on influenza were sent to subjects participating in ongoing placebo-controlled intervention studies with vitamin D supplementation, up until the end of April 2010. Results: Five hundred and sixty-nine subjects from 10 different clinical trials were included in the study, of whom 289 were randomized to receive vitamin D (1111-6800 IU/day) and 280 to receive placebo. Influenza-like disease during the previous fall/winter was reported in 38 subjects in the vitamin D group and 42 in the placebo group (non-significant), of whom 25 and 26 subjects, respectively, fulfilled our clinical criteria for influenza. In these latter subjects, the duration of illness was significantly longer among those in the vitamin D group than among those in the placebo group (median 7 (range 2-60) days vs median 4 (range 2-18) days; p = 0.007). However, this difference was not statistically significant if all 38 (vitamin D) and 42 (placebo) subjects who reported symptoms were included. Conclusion: Our results do not support the hypothesis that high doses of vitamin D supplementation will have a pronounced effect on influenza-like disease in populations not targeted for high influenza risk.</p>

AB - <p>Background: Vitamin D deficiency has been associated with a number of diseases, including influenza. Whether or not this reflects a causal relationship is unknown. We therefore wanted to examine if supplementation with vitamin D would affect the incidence and severity of influenza-like disease. Methods: Questionnaires on influenza were sent to subjects participating in ongoing placebo-controlled intervention studies with vitamin D supplementation, up until the end of April 2010. Results: Five hundred and sixty-nine subjects from 10 different clinical trials were included in the study, of whom 289 were randomized to receive vitamin D (1111-6800 IU/day) and 280 to receive placebo. Influenza-like disease during the previous fall/winter was reported in 38 subjects in the vitamin D group and 42 in the placebo group (non-significant), of whom 25 and 26 subjects, respectively, fulfilled our clinical criteria for influenza. In these latter subjects, the duration of illness was significantly longer among those in the vitamin D group than among those in the placebo group (median 7 (range 2-60) days vs median 4 (range 2-18) days; p = 0.007). However, this difference was not statistically significant if all 38 (vitamin D) and 42 (placebo) subjects who reported symptoms were included. Conclusion: Our results do not support the hypothesis that high doses of vitamin D supplementation will have a pronounced effect on influenza-like disease in populations not targeted for high influenza risk.</p>

KW - H1N1

KW - influenza

KW - randomized clinical trial

KW - vitamin D

KW - RESPIRATORY-TRACT INFECTION

KW - YOUNG FINNISH MEN

KW - 25-HYDROXYVITAMIN-D

KW - ASSOCIATION

KW - RISK

U2 - 10.3109/00365548.2011.621446

DO - 10.3109/00365548.2011.621446

M1 - Article

JO - Scandinavian Journal of Infectious Diseases

JF - Scandinavian Journal of Infectious Diseases

SN - 0036-5548

IS - 2

VL - 44

SP - 126

EP - 132

ER -