CARMEL, Ind., May 29, 2013 /PRNewswire/ -- Cancer is the No. 1 health concern among our country's middle-income Americans, according to a new study released by Washington National Institute for Wellness Solutions (IWS). The study, Middle-Income America's Perspectives on Critical Illness and Financial Security, which surveyed 1,001 Americans ages 30 to 66 with an annual household income of between $35,000 and $99,999, found that 79% are somewhat concerned or very concerned about a cancer diagnosis, followed by heart disease (74%), stroke (70%), and Alzheimer's disease (60%). The specific cancer types that elicit the most concern correlate heavily with gender. Prostate, colon and lung cancer are the largest concerns for men; for women, breast cancer is the predominant concern. Highest concerns by critical illness type Those concerned about cancer and heart disease feel most vulnerable to healthcare costs and the life-threatening nature of these illnesses. People most concerned about stroke and Alzheimer's/dementia, by contrast, feel vulnerable on quality-of-life issues and being able to maintain an independent life after a diagnosis and treatment. The study also found that people tend to be more concerned about a loved one being diagnosed than themselves. Nearly half (47%) say they would be more concerned if a parent or child were diagnosed with cancer than themselves (38%). "Practice healthy habits and seek regular care," said Barbara Stewart, President of Washington National Insurance Company. "A portion of critical illness diagnoses are attributable to genetics but others are attributable as result of unhealthy habits. Taking control of your wellness today may help to improve your odds for a long, healthy life." External treatment sources Many middle-income Americans equate health with wealth. About half (53%) strongly agree with the proposition that "people with more money receive higher-quality medical treatment". Uninsured consumers and African-Americans are more likely to feel that wealth influences treatment quality.