Editing Penetrance (section)

=== Environmental modifiers ===
Exposure to environmental and lifestyle factors such as [[Chemical substance|chemicals]], [[Dieting|diet]], [[Alcoholic beverage|alcohol intake]], [[Drug|drugs]] and [[Stress (biology)|stress]] are some of the factors that might influence disease penetrance.<ref name=":0" /><ref>{{Cite journal |last1=Cavalli |first1=Giacomo |last2=Heard |first2=Edith |date=24 July 2019 |title=Advances in epigenetics link genetics to the environment and disease |url=https://www.nature.com/articles/s41586-019-1411-0 |journal=Nature |language=en |volume=571 |issue=7766 |pages=489–499 |doi=10.1038/s41586-019-1411-0 |pmid=31341302 |bibcode=2019Natur.571..489C |issn=1476-4687 |access-date=15 February 2024 |archive-date=9 February 2024 |archive-url=https://web.archive.org/web/20240209193940/https://www.nature.com/articles/s41586-019-1411-0 |url-status=live }}</ref> For example, several studies of BRCA1 and BRCA2 mutations, associated with an elevated risk of [[Breast cancer|breast]] and [[ovarian cancer]] in women, have examined associations with environmental and behavioral modifiers such as [[Pregnancy|pregnancies]], history of [[Breastfeeding|breast feeding]], [[smoking]], diet, and so forth.<ref>{{Cite journal |last1=Tryggvadottir |first1=Laufey |last2=Olafsdottir |first2=Elinborg J. |last3=Gudlaugsdottir |first3=Sigfridur |last4=Thorlacius |first4=Steinunn |last5=Jonasson |first5=Jon G. |last6=Tulinius |first6=Hrafn |last7=Eyfjord |first7=Jorunn E. |date=1 October 2003 |title=BRCA2mutation carriers, reproductive factors and breast cancer risk |journal=Breast Cancer Research |volume=5 |issue=5 |pages=R121-8 |doi=10.1186/bcr619 |doi-access=free |issn=1465-542X |pmc=314423 |pmid=12927042 }}</ref>