This is expected, because of the differences between individual studies in, for example, case ascertainment, study population characteristics, exposure measurement, and whether crude or adjusted risk estimates were reported.
Despite some individual differences between the study populations, no significant findings were obtained by heterogeneity testing, and the pooled ORs for rs961616 and rs2297926 both remained above the threshold of significance (Figure 2), thus suggesting MAMDC1 as a candidate gene in SLE susceptibility.
In order to assess the influence of missing data on the outcome, an analysis was made of whether the mean values for continuous variables or the distribution of categorical variables differed between the study populations and the excluded individuals.
The number of included individuals in the study populations varied between 16 and 341 and in the control groups between 12 and 372.
Supplementary Figure 6 Comparison of CDTS between study populations.
The differences in our descriptive results may be due to the age difference between the study population groups and individual biological variations with regard to limited life expectancy.
We compared mean values or distributions of variables describing the characteristics of individuals and their households between the study population and those excluded (Supplementary Tables 8 and 9).
Median distance between advertising individuals in the study population was 0.98 m (range, 0.38 2.69 m, n = 15).
If exposure assessment was performed to assess exposure for previously defined homogeneous exposure categories, there is no direct connection between the individuals in the study population and the exposure assessment, and therefore this criterion needs less stringent application.
These data sources have been described in previous studies in this population (Olsen et al, 1997; Sorensen et al, 2000; Friis et al, 2001) Prescriptions of AHT medications were ascertained from the Pharmacoepidemiological Prescription Database for individuals in the study population between the years 1989 and 2002.
