Petersen, Inge
Pedersen, Nancy L.
Rantanen, Taina
Kremen, William S.
Johnson, Wendy
Panizzon, Matthew S.
Christiansen, Lene
Franz, Carol E.
McGue, Matt
Christensen, Kaare
Hamdi, Nayla R.
Krueger, Robert F.
Reynolds, Chandra
Age-related decline in grip strength predicts later life disability, frailty, lower well-being and cognitive change. While grip strength is heritable, genetic influence on change in grip strength has been relatively ignored, with non-shared environmental influence identified as the primary contributor in a single longitudinal study. The extent to which gene-environment interplay, particularly gene-environment interactions, contributes to grip trajectories has yet to be examined. We considered longitudinal grip strength measurements in seven twin studies of aging in the Interplay of Genes and Environment across Multiple Studies consortium. Growth curve parameters were estimated for same-sex pairs, aged 34–99 (N = 10,681). Fisher’s test for mixture distribution of within-monozygotic twin-pair differences (N = 1724) was performed on growth curve parameters. We observed significant gene-environment interaction on grip strength trajectories. Finally, we compared the variability of within-pair differences of growth curve parameters by APOE haplotypes. Though not statistically significant, the results suggested that APOE ɛ2ɛ2/ɛ2ɛ3 haplotypes might buffer environmental influences on grip strength trajectories.
GxE in psychiatry may explain why environmental risk factors have big impact in some individuals but not in others, and conversely why relatives that are genetically at risk for disease do not all develop disease. Here we discuss two novel methods that use an aggregate genome-wide measure of genetic risk to detect GxE and estimate its effect in the population using data currently available and data we anticipate will be available in the near future. The first method exploits summary statistics from large-scale genome-wide association studies ignorant of the environmental conditions and detects GxE in an out-of-sample risk-profiling framework. The second method relies on larger samples and is based on a mixed linear model framework. It estimates variance explained directly from single nucleotide polymorphisms and environmental measures. Both methods have great potential to improve public health interventions focusing on risk-based screening that is informed by both genetic and environmental risk factors.
Gage, Suzanne H.; Davey Smith, George; Ware, Jennifer J.; Flint, Jonathan; Munafò, Marcus R.; Gibson, Greg
As our understanding of genetics has improved, genome-wide association studies (GWAS) have identified numerous variants associated with lifestyle behaviours and health outcomes. However, what is sometimes overlooked is the possibility that genetic variants identified in GWAS of disease might reflect the effect of modifiable risk factors as well as direct genetic effects. We discuss this possibility with illustrative examples from tobacco and alcohol research, in which genetic variants that predict behavioural phenotypes have been seen in GWAS of diseases known to be causally related to these behaviours. This consideration has implications for the interpretation of GWAS findings.
G. E. Moore claimed to know a variety of commonsense propositions. He is often accused of being dogmatic or of begging the question against philosophers who deny that he knows such things. In this paper, I argue that this accusation is mistaken. I argue that Moore is instead guilty of answering questions of the form Do I know p? in bad faith.
In this piece, the author experiments with re-presenting particular stories through poetic texts that contextualize and honor difference in experience between GED students and instructors. These poetic re-presentations stem from an ongoing study that explores (a) adult basic education instructors' perceptions of their pedagogy and interaction with their students, and (b) adult student experiences in GED classes as well as perceptions of their instructors. The poems are constructed entirely from the words of the participants to capture the tenor of self-disclosure and experience that was shared with the author and to draw the reader toward these experiences. The poems are written in three columns, representing three voices-two students and one instructor. The author hopes that as the reader moves along the text in a weaving pattern, one voice is not privileged over the others as similar and divergent views are expressed.