cholecalciferol and Influenza--Human

In a prior randomized trial, we found that the incidence of influenza A was less in the vitamin D3 group than among those on placebo, but the total incidence of either influenza A or B did not differ between groups. In this trial, the incidence of influenza A or B was less in the vitamin D3 group than in the placebo group only during the first half of the study. To elucidate whether vitamin D3 has preventive actions against influenza A, we conducted another trial during the 2009 pandemic of the H1N1 subtype of influenza A. Students (n = 247) of a Japanese high school were randomly assigned to receive vitamin D3 supplements (n = 148; 2000 IU per day) or a placebo (n = 99) in a double-blind study for 2 months. The primary outcome was incidence of influenza A diagnosed by a rapid influenza diagnostic test by medical doctors. Influenza A was equally likely in the vitamin D3 group (20/148: 13.5%) compared with the placebo group (12/99: 12.1%). By post hoc analysis, influenza A occurred significantly less in the vitamin D3 group (2/148: 1.4%) compared with the placebo group (8/99: 8.1%) (risk ratio, 0.17; 95% confidence interval, 0.04 to 0.77; P = 0.009) in the first month. However, during the second month, the vitamin D3 group experienced more events and effectively caught up with the placebo group. Vitamin D3 supplementation did not lower the overall incidence of influenza A during the 2009 H1N1 pandemic. A post hoc analysis suggests that the initial benefit during the first month of treatment was lost during the second month.

Topics: Adolescent; Cholecalciferol; Dietary Supplements; Double-Blind Method; Female; Humans; Influenza A Virus, H1N1 Subtype; Influenza, Human; Japan; Male

To our knowledge, no rigorously designed clinical trials have evaluated the relation between vitamin D and physician-diagnosed seasonal influenza.. We investigated the effect of vitamin D supplements on the incidence of seasonal influenza A in schoolchildren.. From December 2008 through March 2009, we conducted a randomized, double-blind, placebo-controlled trial comparing vitamin D(3) supplements (1200 IU/d) with placebo in schoolchildren. The primary outcome was the incidence of influenza A, diagnosed with influenza antigen testing with a nasopharyngeal swab specimen.. Influenza A occurred in 18 of 167 (10.8%) children in the vitamin D(3) group compared with 31 of 167 (18.6%) children in the placebo group [relative risk (RR), 0.58; 95% CI: 0.34, 0.99; P = 0.04]. The reduction in influenza A was more prominent in children who had not been taking other vitamin D supplements (RR: 0.36; 95% CI: 0.17, 0.79; P = 0.006) and who started nursery school after age 3 y (RR: 0.36; 95% CI: 0.17, 0.78; P = 0.005). In children with a previous diagnosis of asthma, asthma attacks as a secondary outcome occurred in 2 children receiving vitamin D(3) compared with 12 children receiving placebo (RR: 0.17; 95% CI: 0.04, 0.73; P = 0.006).. This study suggests that vitamin D(3) supplementation during the winter may reduce the incidence of influenza A, especially in specific subgroups of schoolchildren. This trial was registered at https://center.umin.ac.jp as UMIN000001373.

Topics: Adolescent; Body Height; Body Weight; Child; Cholecalciferol; Dietary Supplements; Double-Blind Method; Female; Humans; Influenza A virus; Influenza, Human; Japan; Male; Patient Selection; Placebos; Risk

Topics: Aged; Cholecalciferol; Common Cold; Dose-Response Relationship, Drug; Female; Humans; Influenza, Human; Middle Aged; New York; Randomized Controlled Trials as Topic; Seasons; Treatment Outcome

Research to detect new factors contributing to the etiology of acute leukemia (AL) is urgently needed. Located between latitudes 65 degrees and 70 degrees north, the population in northern Finland is exposed to extreme seasonal alterations of ultraviolet-B light and temperature. There is also a seasonal variation of both the 25(OH)- and 1,25(OH)2-D3 vitamin serum concentrations. In the present work, the frequencies of different types and age-groups at diagnosis of AL were compared during the dark and light months of the year, to uncover seasonality. Between January 1972 and December 1986, 300 consecutive patients aged >/=16 years and diagnosed as having AL were enrolled. The observed mean monthly global solar radiation, temperature measurements, and influenza epidemics were compared with the monthly occurrence of AL. Both acute lymphoblastic leukemia (ALL) (p=0.006) and total AL (p=0.015) were diagnosed excessively in the dark and cold compared with light and warm period of the year. There was a tendency for de novo leukemia to increase also in the dark and cold, but for acute myeloid leukemia (AML) patients the excess was not significant. Age >/=65 was strongly associated with the dark and cold season (p=0.003). Significantly more ALL (p=0.005) and de novo leukemias (p=0.029) were observed during influenza epidemics than during nonepidemic periods. However, a seasonality, i. e., the fluctuation of numbers of AL cases, was not determined, either monthly or during different photo- and temperature periods or influenza epidemics; this might be due to the small numbers of patients studied. Nevertheless, it is hypothesized that sunlight deprivation in the arctic winter can lead to a deficiency of the 1, 25(OH)2D3 vitamin, which might stimulate leukemic cell proliferation and block cell differentiation through dysregulation of growth factors in the bone marrow stromal cells, causing one mutation and an overt ALL in progenitor cells damaged during the current or the previous winter by influenza virus, the other mutation.

Topics: Acute Disease; Adolescent; Adult; Aged; Cholecalciferol; Cold Temperature; Disease Outbreaks; Female; Finland; Humans; Influenza, Human; Leukemia; Male; Middle Aged; Precursor Cell Lymphoblastic Leukemia-Lymphoma; Risk Factors; Seasons; Ultraviolet Rays