Anxiety is a common mental health problem, and middle-aged women are more likely to be affected. Although many factors may be to blame, a new study revealed a surprising cause — belly fat.

Everyone knows that stress eating contributes to thicker waistlines. But the new study, which analyzed data from more than 5,580 middle-aged Latin American women asked a different question — could greater abdominal fat increase stress and the risk of anxiety.

The study, which was published in the journal Menopause, used waist-to-height ratio — the same indicator shown to be the best assessment of cardiometabolic risk — to measure the link to anxiety. A woman is considered obese if her waist measures more than half of her height.

The study found that 58 percent of the women were post-menopausal and that 61.3 percent reported anxiety. It also found that those women in the middle and upper thirds of waist-to-height ratios were significantly more likely to have anxiety. Women in the upper third were more likely to actually display signs of anxiety compared with women in the lower two-thirds.

"Hormone changes may be involved in the development of both anxiety and abdominal obesity because of their roles in the brain as well as in fat distribution," said Dr. JoAnn Pinkerton, executive director of the The North American Menopause Society.

"This study provides valuable insights for healthcare providers treating middle-aged women, because it implies that waist-to-height ratio could be a good marker for evaluating patients for anxiety," she said.

Want a natural way to help reduce anxiety? Try chewing gun. Numerous studies have found that chewing gum lowers stress and anxiety by reducing levels of cortisol, the stress hormone.

A Japanese study found that chewing stimulated up to eight areas of the brain, and other studies have found that chewing gum, especially the minty varieties, increases alertness and overall performance. An Australian study found that chewing gum improved the baseline scores of stressed participants up to 109 percent over non-gum chewers.

You can also experiment with aromatherapy. A study at the Memorial Sloan-Kettering Hospital found that patients exposed to the scent of vanilla while undergoing magnetic resonance imaging (MRI) reported feelings of claustrophobia were reduced by 63 percent.