.001 but the adjusted estimates are less than .00001. In other words, the effects of each SNP are very small and are quite sensitive to the inclusion or exclusion of control variables, which may have to do with our fairly small sample size. For instance, Vrieze and colleagues (2012) stated that studies expecting to achieve genome-wide significance levels of p < 5 10–8 need to exceed 50,000 individuals. Many health surveys used by demographers, especially those with genome-wide data, are significantly smaller than the 50,000 observations. This limitation should be considered by future researchers who are interested in genome-wide studies.
