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From the Journals

Does Age at Menopause Predict Asthma Risk in Women?

Women who experienced natural menopause between ages 40-44 had a 30% lower asthma risk compared to those with later menopause (ages 50-54), suggesting timing of menopause may influence respiratory health outcomes in postmenopausal women.

Conexiant

Women who experienced natural menopause between the ages of 40 and 44 years had a 30% lower risk of developing asthma compared with those who experienced menopause at ages 50 to 54 years, according to a study.

In the study, published in Menopause, investigators analyzed the data from 14,406 postmenopausal women (weighted N = 3.5 million) participating in the Canadian Longitudinal Study on Aging (CLSA). They identified 732 incident asthma cases (5.08%). The overall asthma incidence rate was 2.82 per 1,000 person-years across 259,464.2 person-years of follow-up.

The multivariable Cox regression analysis revealed a hazard ratio (HR) of 0.7 (95% confidence interval [CI] = 0.49–0.95) for asthma risk in women with early natural menopause (ages 40 to 44 years) compared with the reference group (ages 50 to 54 years).

The investigators analyzed two distinct CLSA cohorts:

  • A tracking cohort (n = 21,241, 10,835 females) assessed via telephone interviews
  • A comprehensive cohort (n = 30,097, 15,320 females) evaluated through in-person interviews and physical examinations.

The study population distribution by age at natural menopause was:

  • Ages 40 to 44 years: 7.4% (n = 1,065)
  • Ages 45 to 49 years: 22.5% (n = 3,247)
  • Ages 50 to 54 years: 51.3% (n = 7,386)
  • Ages ≥ 55 years: 18.8% (n = 2,708).

Data collection occurred every 3 years across three cycles, with a 21.42% attrition rate by the second follow-up.

Population Characteristics The study population (mean age = 61.4 years, standard deviation [SD] = 10.0) showed the following characteristics:

  • White ethnicity: 95.5%
  • Living with partner: 62.2%
  • Former smokers: 62.2%
  • Regular alcohol consumption (> once weekly): 52.5%
  • Regular physical activity: 58.5%
  • No depression symptoms: 83.5%
  • Mean BMI: 27.2 kg/m² (SD = 5.6)
  • Urban residents: 80.0%.

Mean BMI varied by age at natural menopause:

  • Ages 40 to 44 years: 28.0 kg/m² (SD = 6.4)
  • Ages 45 to 49 years: 27.1 kg/m² (SD = 5.5)
  • Ages 50 to 54 years: 27.0 kg/m² (SD = 5.6)
  • Ages ≥ 55 years: 27.5 kg/m² (SD = 5.5).

Additional Risk Factors The analysis identified several factors associated with asthma risk:

  • Depression: HR = 1.4 (95% CI = 1.1–1.8)
  • Allergies: HR = 1.8 (95% CI = 1.5–2.3)
  • BMI: HR = 1.1 (95% CI = 1.0–1.1).

Methodology Details Researchers employed multiple imputation by chained equations to address missing data:

  • Age at menarche: 23.1% missing
  • Oral contraceptive use: 18.4% missing
  • Number of births: 13.9% missing.

BMI measurements differed between cohorts:

  • Self-reported in tracking cohort
  • Physically measured in comprehensive cohort.

Depression was assessed using the Center for Epidemiological Studies short Depression scale (CES-D10), with scores ≥ 10 indicating depressive symptomatology.

Statistical analyses included Cox proportional hazard models with BMI as a time-varying covariate and robust standard errors to address violations of the proportional hazard assumption. Interaction terms for BMI, smoking, and hormone therapy with age at natural menopause showed no significant interactions.

Study limitations included potential recall and misclassification biases from self-reported data, though previous research demonstrated high accuracy for self-reported asthma status and age at menopause. The predominantly White patient sample (95%) affected generalizability to other populations.

The authors declared having no competing interests.