Article type
Year
Abstract
Background:
There is considerable controversy on whether race modifies the effect of genetic risk factors for common diseases.Objectives:
To explore the variation in the frequencies and effect sizes within and between racial groups for specific genetic markers implicated in the susceptibility to various diseases.Methods:
We evaluated 41 meta-analyses of genetic association studies that provided adequate data for racial subgroup analyses on a total of 495 case-control studies. For each eligible meta-analysis, we estimated race-specific weighted frequencies of the genetic marker of interest in the control groups and race-specific summary odds ratios. Racial descent groups were categorized as European, East Asian, African and other. Pair-wise comparisons were performed with general variance models. Between-study heterogeneity was assessed by the Q and I2 statistics.Results:
The between-race variance for the weighted control frequencies was larger than the within-race variance in 22 meta-analyses. Conversely, the between-race variance for the race-specific summary odds ratios was larger than the within-race variance in only 6 meta-analyses.When we compared the weighted control frequencies, statistically significant differences were seen in 21/32 (66% [95% confidence interval (CI) 47-81%]) European vs. East Asian descent comparisons, 7/18 (39% [95% CI 17- 64%]) European vs. African descent comparisons, and 10/16 (63% [95% CI 35-85%]) East Asian vs. African descent comparisons. In pair-wise comparisons between the race-specific odds ratios, statistically significant differences were seen in only 3/32 (9% [95% CI, 2-25%]) European vs. East Asian descent comparisons, 2/18 (11% [95% CI 1-17%]) European vs. African descent comparisons, and in none of the 16 (0% [95% CI 0-9%]) East Asian vs. African descent comparisons. Control frequencies showed large heterogeneity between the various racial descent groups in 24 cases (59%), while only in 3 cases (7%) for the genetic effects (odds ratios).