Oh, it reduces his cholesterol level[0]. But he has at least one allele that increases the risk of myopathy when taking simvastatin (Assuming there were no milkmen - I do look quite a bit like him - I'm homozygous, and this allele is not terribly rare).

The part about being asian is that asians tend not to catabolize statins as effectively, so his plasma levels are probably higher, since I found out he was taking a full "white person dose" despite advisories that simvastatin should be given at half dose for asians.

[0]I also recall hearing somewhere from a biochemist that while statins decrease cholesterol levels in asians the effect on coronary heart disease (which is what your really care about) is attenuated, and that there may be a secondary mechanism for CHD in asians... But I cannot find the source he was quoting.