Table 3

Associations Between Airflow Limitation According to Various Definitions and Outcomes

OutcomeFR+/LLN−a (n = 297)FR+/LLN+ (n = 532)
Chronic cough1.001.81 (1.24–2.65)
Chronic phlegm1.002.13 (1.41–3.21)
Chronic bronchitis1.001.98 (1.12–3.48)
Wheeze1.002.11 (1.52–2.93)
MRC dyspnea scaleb1.002.04 (1.48–2.81)
SF-12 Physical scalec1.00−2.39 (<.01)
SF-12 Mental scalec1.00−1.10 (.11)
Exacerbation1.001.43 (1.01–2.02)
Cardiovascular disease1.000.79 (0.55–1.13)
  • FR = fixed ratio; LLN = lower limit of normal; MRC = Medical Research Council; SF-12 = Short Form 12-item health survey.

    Notes: Multiple logistic regression, except as otherwise noted. All models adjusted for age-group (<60 years), sex, and ever smoking. Data are presented as odds ratios (95% CI) or parameter estimate (P value) from regression analysis.

  • a Reference group.

  • b Ordinal logistic analysis.

  • c Multiple linear regression analysis.