About the data: We used the family income data from the 2013 American Community Survey. This counts only families, which the government defines as households with two or more people related by birth, marriage or adoption. The graph focuses on families living in the country's 30 most populous cities.
Foot, leg, and ankle swelling. Painless swelling of the feet and ankles is a common problem, especially among older people. Abnormal buildup of fluid in the ankles, feet, and legs can cause swelling. This fluid buildup and swelling is called edema. Painless swelling may affect both legs and may include the calves or even the thighs. The effect of gravity makes the swelling most noticeable in the lower part of the body.
Swelling in the ankles and legs is called peripheral edema; it is typically caused by right-sided heart failure. This may lead to nocturnal polyuria, or frequent urination at night. Your body converts the excess fluid into urine, resulting in you waking up repeatedly during the night to urinate.