A unique study looking at breast cancer and body weight found that a person's ethnicity may also play a larger role.
In 1993, researchers at the University of Hawaii Cancer Center and the University of Southern California began tracking women from five different ethnic groups: Japanese, Hawaiian, African-American, Latino and Caucasian. The study continues nearly 20 years later.
"Of about 90,000 in our study, we have had 3,000 with breast cancer so far," said researcher Lynne Wilkens.
It all began with a baseline health survey of women of all shapes and sizes. It asked women questions like whether they smoked or how often they consumed alcohol and how much they exercised.
"We looked at height, weight, weight gain from age 21 and body mass index," said biostatistician Kami White.
Body mass index, or BMI, measures a person's body size and ratio of muscle and body fat.
They study also looked at where the post-menopausal women carried their weight on their bodies.
"People who carry more weight in their upper body have more risk. That's more metabolically active fat and have more risk," said Wilkens.
"Many of the subjects came here to the UH Cancer Center or other local laboratories for follow-up screenings which analyzed their blood and urine samples.
The tests looked for cholesterol, evidence of inflammation as well as other markers like insulin and antioxidants.
The results validated the link between obesity and cancer.
"Heavier women are exposed to more estrogen and we looked across our ethnic groups and found all of them had an increased risk of breast cancer," said Wilkens.
The risk was 20 percent, but the study also found that in Hawaiians and Japanese that risk jumped to 50 percent.
Wilkens said the risk increased for other diseases like diabetes too.
The findings were just published this year.
"You want to keep a healthy lifestyle, whether that means increasing physical activity, maintaining a healthy body weight and make sure you are getting preventative screenings," said White. "There are things people can do to keep a healthy lifestyle and that's the message we want to carry forward."
Two decades of research hoping to save lives.