How genetic factors determine a persons level of health?

Answer 1

One way genetic factors determine a person's level of health is by being responsible for the disease state. Such diseases can be inherited. Whether they are or not depends which of each of the pairs of parents' chromosomes are passed onto offspring. If genes are inherited that directly cause disease, the individuals level of health is lower than that of healthy individuals (who do not possess the offending gene).

But some genes do not necessarily cause disease, and instead predispose a person to a disease. So these genetic factors determine the fitness of the individual relative to those without those particular genes. Now given a population exposed to the same environmental stimuli, including infectious organisms, an individual genetically more susceptible who acquires the disease can be said to have a genetically determined lower level of health.

Without respect to diseases, genetics influence the effect toxins have on the body. Detoxification by liver is strongly genetically regulated, with some individuals having a more active variant of a particular liver enzyme and/or higher amounts expressed. The link to health is linked to environmental factors. Some substances acted on the by liver are actually made more toxic and individuals with more of the "detoxifying" enzyme would have poorer health. On the flip side, other substances are detoxified and those individuals with increased enzyme activity are healthier. Therefore, different exposures predispose some to better health and others to poorer health.