Although these metabolites have a good correlation with each other, our analyses show a difference in association between individual PAH metabolites and obesity and body weight outcomes.
The analyses presented here are more complicated in that they represent a difference in association with age between two or more risk groups.
Currently, it is uncertain whether such a difference in association also exists between socioeconomic position and physical activity in these ethnic groups.
For instance, a difference in association between adiponectin, a hormone secreted by adipose tissue, and insulin resistance, a known risk factor for albuminuria, has been observed between ethnic groups [ 35- 38].
In addition, reanalysis of IDDM2 genotypes in T1D families did not support the original finding of a difference in association between VNTR lineages that had previously enabled the exclusion of intragenic polymorphisms (Barratt et al. 2004).
If studies that detected a difference in association by ER/PR status were more likely to be published, our results for parity and age at first birth could be biased.
Whether this diversity in allelic association, in absence of any allelic flip, is due to a difference in association with the disorder or is generated due to type I error in different studied population merits further investigation in large cohort of subjects.
When conducting case-case analysis, we observed a difference in the association of CDKN2BAS-rs1011970 with invasive BC and BCIS, suggesting an association with BCIS only, although this difference was not statistically significant after adjusting for multiple comparisons (P = 0.006).
Although social participation may also have a protective effect, the association was weaker, and we did not find a difference in the association comparing bonding and bridging structural social capital.
A number of previous studies have compared maternal-offspring to paternal-offspring adiposity associations as described above, and considering this previous evidence together with our large study, we would conclude that there is little evidence to support a difference in the association of maternal BMI with offspring adiposity compared with the association of paternal BMI with offspring adiposity.
