Larger magnitude of association between genetic risk score for BMI and BMI in later birth cohorts
WEDNESDAY, July 6, 2016 (HealthDay News) — The magnitude of the association between a multilocus genetic risk score for body mass index (GRS-BMI) and BMI is larger for individuals born in later birth cohorts, according to a study published online July 5 in the Journal of the American Medical Association.
Stefan Walter, Ph.D., from the University of California, San Francisco, and colleagues conducted an observational study involving 8,788 adults in the U.S. Health and Retirement Study born between 1900 and 1958. Participants had up to 12 BMI assessments from 1992 to 2014. A multilocus GRS-BMI was calculated as the weighted sum of alleles of 29 single-nucleotide polymorphisms associated with BMI.
The researchers found that among 7,482 white participants and 1,306 black participants, GRS-BMI was significantly correlated with BMI. GRS-BMI accounted for 0.99 and 1.37 percent of the variation in BMI in white and black participants, respectively. More recent birth cohorts had a larger magnitude of the associations of GRS-BMI with BMI in multilevel models accounting for age. Among white participants, each unit higher GRS-BMI correlated with a difference in BMI of 1.37 and 0.17 if born after 1943 and before 1924, respectively. For black participants, the corresponding values were 3.7 and 1.44, respectively.
“This suggests that associations of known genetic variants with BMI may be modified by obesogenic environments,” the authors write.
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