Table 2.

Overview of aims, participants, data sources, and statistical methods used in the studies of the D-tect project, with vitamin D exposure before or during pregnancy.

Outcomes	Aim	Participants	Data Source	Statistical Methods
Pre-eclampsia [19]	To examine whether exposure to extra vitamin D from food fortification was associated with a decrease in the risk of preeclampsia	All nulliparous women giving birth after gestational week 22 in the period 1 June 1983 to the 31 August 1988	Civil registration numbers linked to the Danish National Patient Registry	Logistic regression models
Live births in women diagnosed with infertility [23]	To examine the association between extra vitamin D from a mandatory margarine fortification program and chance of live birth among infertile women	All women diagnosed with primary infertility from 1 September 1986, to 31 August 1991. Any live birth for each woman in the cohort within a follow-up period of 12 months after the initial infertility diagnosis date.	Civil registration numbers linked to the Danish National Patient Registry, the Danish Medical Birth Register, the Danish Infertility Cohort, and the Danish In Vitro Fertilization Registry	Logistic regression models