Reply to SS Harris

Division of Epidemiology
Norwegian Institute of Public Health
PO Box 4404 Nydalen
N-0403 Oslo
Norway
E-mail: lars.christian.stene{at}fhi.no

Dear Sir:

We thank Harris for her interest in our work. As we stated in our article (1), the reasons that our results on vitamin D supplements other than cod liver oil differed from those of Hyppönen et al (2) are not known. However, as we stated in our article, we have not ruled out the possible protective effect of vitamin D against type 1 diabetes at doses >10 µg/d, and we agree with Harris that this is a possible explanation.

REFERENCES

1. Stene LC, Joner G, and the Norwegian Childhood Diabetes Study Group. Use of cod liver oil during the first year of life is associated with lower risk of childhood-onset type 1 diabetes: a large, population-based, case-control study. Am J Clin Nutr 2003;78:1128–34.
2. Hyppönen E, Läärä E, Reunanen A, Järvelin MR, Virtanen SM. Intake of vitamin D and risk of type 1 diabetes: a birth-cohort study. Lancet 2001;358:1500–3.