Obesity May Pose Breathing Threat for Women

Obesity may put women at a higher risk for airway obstructive diseases, a Korean population-based cohort study suggested.

In an adjusted model, premenopausal women with severe obesity had a 67% higher risk for chronic obstructive pulmonary disease (COPD; HR 1.67, 95% CI 1.54-1.81), while postmenopausal women had a 57% elevated risk (HR 1.57, 95% CI 1.50-1.65), compared with women of normal weight, reported Do-Hoon Kim, MD, PhD, of Korea University Ansan Hospital, and colleagues in Menopause, the journal of the North American Menopause Society (NAMS).

Although not to the same extent, non-severe obesity and overweight also increased women’s risk of developing COPD — regardless of menopausal status — versus a reference BMI of 18.5 to 23:

• Premenopause BMI 23-25: HR 1.11 (95% CI 1.07-1.16)
• Postmenopause BMI 23-25: HR 1.05 (95% CI 1.02-1.07)
• Premenopause BMI 25-30: HR 1.26 (95% CI 1.21-1.31)
• Postmenopause BMI 25-30: HR 1.20 (95% CI 1.17-1.23)

This link wasn’t limited to just BMI, though, as Kim’s group found the same positive correlation between waist circumference and risk for COPD. Premenopausal women with a waist circumference of 95 cm (37 in) or higher saw the biggest increased risk for COPD (HR 1.74, 95% CI 1.57-1.93) compared with a reference waist circumference of 65 to 75 cm (26 to 30 in).

These patterns were similar when the researchers looked at the risk for asthma. Likewise, both pre- and postmenopausal women with higher BMI and waist circumference had significantly higher risks for developing asthma.

Looking at the other end of the spectrum, pre- and postmenopausal women who were underweight did not have a higher risk for these airway obstructive diseases, with the exception of postmenopausal women with a BMI under 18.5 or waist circumference under 65 cm who showed a modestly higher risk for COPD, but not asthma.

However, Kim’s group pointed out that several prior studies have suggested a relationship between underweight and incidence of COPD.

“This study highlights yet another detrimental effect of obesity and abdominal adiposity in women and specifically identified that women with a high BMI and/or waist circumference had a greater risk of developing COPD and asthma,” said Stephanie Faubion, MD, MBA, medical director of NAMS, in a statement. “In addition to avoiding tobacco use, maintaining a healthy body weight and composition may help reduce the incidence of COPD and asthma in women.”

Inflammation is one likely culprit behind this association, Kim and colleagues suggested. “Increased adiposity associated with obesity acts by increasing the levels of pro-inflammatory cytokines, such as tumor necrosis factor-alpha and interleukin-6, and decreasing the levels of adiponectin, thereby increasing systemic inflammation,” they wrote.

For the analysis, the researchers used national health insurance claims data for 1,644,635 women ages 30 and older enrolled in the Korean National Health Insurance Service, who had no prior diagnosis of COPD or asthma. Women who previously underwent a hysterectomy were excluded.

They categorized BMI according to the WHO Western Pacific Region’s categories: underweight (under 18.5), normal weight (18.5-23), overweight (23-25), obesity (25-30), and severe obesity (30+).

Kim and team adjusted their model for age, smoking status, alcohol intake, income level, exercise, hypertension, dyslipidemia, and hormone therapy usage.

The study was exclusive to South Korean women, which was a limitation, the researchers acknowledged. In addition, menopausal status was sometimes incorrectly self-reported.