Even when a person is at risk for developing HD there are many things he or she can do about it. Yes, everyone with the HD allele will eventually display symptoms of HD. However, the expression of these symptoms is subject to great variability. For example, studies of the HD population in Venezuela revealed that there is great variability in the age of onset (the age at which symptoms first appear) of HD. While the number of repeats of the CAG codon is the most important factor in determining age of onset, it is not the only factor. There may be a big difference in the age at which two individuals with the exact same repeat length-and even genetically identical twins-begin expressing symptoms of HD. Researchers found that, after controlling for repeat length, about 60% of the variance in age of onset is environmental (“variance” is a statistical measure of variability). This important finding means that genes do not completely determine the expression of HD: the environment plays an important role. The implication is that everyday practices regarding diet, exercise, and stress management can greatly influence the onset and progression of HD. While these practices are by no means “cures” or even treatments for HD, they do promote health. Also, it is important to realize that while a correlation may exist between such practices and good health, and even improvement in HD symptoms, that correlation does not mean that the practices are themselves causing the good results. Other factors may be involved. In any event, it is important to consult your medical doctor before making any drastic changes in your lifestyle.
General health promotion strategies address the mental, physical, spiritual, and social connections of who we are and how we live. Through both action and inaction people make choices about their health on a daily basis. Each of us has general health strategies that we are implementing all the time. The purpose of this chapter is to provide information about life practices that promote general health, and to explore how these life practices may affect the way that individuals respond to HD. Despite the fact that people with the HD allele will eventually show symptoms, the expression of these symptoms can be greatly influenced by the lifestyle choices that those individuals make.