Sometimes keeping a healthy weight and a healthy level of physical activity can have unexpected benefits. Who would think there's a link between one's weight and their hearing?
Yet a recent study found that obese women were more likely to experience hearing loss over the long-term than women with a normal, healthy weight.
Accordingly, women with smaller waist circumferences were at lower risk for hearing loss compared to women with larger waist sizes.
Although a woman's weight and waist size influenced her risk of hearing loss on their own, so did her physical activity. The more physically active women had a lower risk of hearing loss than the least physically active women.
Just two hours of walking each week appeared to make a difference in women's risk for hearing loss.
This study, led by Sharon G. Curhan, MD, MSc, of the Department of Medicine at Brigham and Women's Hospital in Boston, compared hearing loss rates among women of different weights and levels of physical therapy.
The researchers compared health information and demographics among 68,421 women who were participating in a large study called the Nurses' Health Study II from 1989 to 2009.
Among the information provided every other year during the study were the women's body mass index (BMI) measurements, their waist circumference and their physical activity.
BMI is a ratio of a person's height to weight and is used to classify whether a person is overweight, underweight or an appropriately normal weight.
A person with a BMI between 18.5 and 25 is considered to have a normal weight, while an overweight BMI is between 25 and 30. An obese person has a BMI between 30 and 40, and a severely obese BMI would be a 40 or greater.
Over an average of 16 years of follow-up, these researchers found 11,286 cases of hearing loss reported among the women.
Women with a higher BMI and a larger waist circumference were found to have a higher likelihood of experiencing hearing loss than women with lower BMIs and smaller waists.
For example, obese women with a BMI above 40 were about 25 percent more likely to have hearing loss than normal-weight women with a BMI less than 25.
Similarly, women whose waist circumference was greater than 35 inches were about 27 percent more likely to have hearing loss than women with a waist circumference of less than 28 inches.
However, the more physically active women were, the less likely they were to experience hearing loss.
Women who ranked in the top one fifth of the group for their level of physical activity were 17 percent less likely to have hearing loss than women in the lowest fifth for physical activity.
Specifically, walking at least two hours a week appeared to reduce women's risk of hearing loss.
When the researchers took into account all three factors together — BMI, waist circumference and physical activity — it was clear that the three together were interacting and contributing to the reduced risk. However, each individual factor of these three also was related to the reduced risk.
Therefore, even if the other two were not present, women's risk of hearing loss was still lower with just one of these three factors.
"Higher BMI and larger waist circumference are associated with increased risk, and higher physical activity is associated with reduced risk of hearing loss in women," the researchers wrote.
"These findings provide evidence that maintaining healthy weight and staying physically active, potentially modifiable lifestyle factors, may help reduce the risk of hearing loss," they wrote.
This study was published in the December issue of the American Journal of Medicine.
The research was funded by the National Institutes of Health and the Vanderbilt University School of Medicine. The authors declared no conflicts of interest.