I think that a lack of exercise is a major factor that can impact both physical and mental health. We know that getting more exercise can help a person have better heart health, blood pressure, and weight. We also know that getting exercise can help make people generally feel better about themselves mentally. I think that this is perhaps the most important factor (that people can actually control) in determining physical and mental health.
A family history of depression or substance abuse (or both, since they could easily be connected) could impact a person's physical and/or mental health. Left untreated, depression caused by chemical imbalances can become severe enough to cause physical symptoms: aches, pains, extreme fatigue for example. A predisposition to addiction leading to substance abuse could certainly cause mental stress and physical problems, like the liver problems alcoholics frequently experience. A person with an addiction will likely not be taking care of him or herself in any aspect of his/her life, which could lead to other physical problems. Even a person without a genetic predisposition to addiction might turn to substance abuse to assuage the pain, which could then lead to an addiction. The mind-body connection has also been studied a great deal by people seeking to determine how our thinking and spirituality might influence our physical health. A