In the same Finnish cohort that found doses of vitamin D in excess of 2,000 IU per day
during infancy to powerfully protect against type 1 diabetes (see sidebar «Vitamin D and Type 1 Diabetes below), regular
supplementation with vitamin D was associated with a 33 percent increased risk of atopy and allergic rhinitis compared to irregular or no
supplementation; among those who supplemented regularly, the data suggested that
supplementation with 2000 IU or more per day may increase the risk of asthma by as much as four times compared to regular
supplementation with lower doses, although the study lacked the statistical power to determine whether or not this apparent effect was due to chance.34