Chronic diseases can be influenced or caused by environmental factors. Asthma and allergies are triggered by things in the environment like dust, mold, fumes and pet dander. Long term exposure to contaminated soil, air or water can lead to kidney disease, immune deficiency or cancer. Obesity rates are higher in areas that lack sidewalks or places to exercise. Heavy metal poisoning from lead and mercury can occur from ingesting or inhaling these substances, leading to issues like anemia, brain damage or neurological problems.