Table 3

Hypothetical examples of individualised predictions by baseline smoking and asthma status in a high-risk occupation: risk difference with and without quitting by age 50s

Predictions by recalled asthma and smoking status for an at-risk occupational group*†Predicted probability (%)Predicted occurrence (1/n persons)Risk category (age in 40s)‡
Smoking status—no asthma or respiratory symptoms
Past smoker2.540Low
Current smoker at mean age 43
Quit smoking by mean age 534.522Low
Continued smoking at 53§27.03.7Very high
Smoking status—adult-onset asthma with wheeze in the last 12 months
Past smoker10.89.3High
Current smoker at mean age 43
Quit smoking by mean age 5316.46.1High
Continued smoking at 53¶42.02.4Very high
  • *Based on a 30 pack-year smoking history starting at age 13 and asthma onset at age 23 years.

  • †Based on a female worker from an at-risk occupation (eg, labourers and related workers such as cleaners, factory workers, farm and/or kitchen hands).

  • ‡Risk categories: minimal risk if predicted occurrence of 1 in >100 similar persons; low risk if 1 in 20–100 persons; moderate risk if 1 in 10–20 persons; high risk if 1 in 5–10 persons and very high risk if 1 in 1.5–5 persons.

  • §Same clinical scenario has been presented in online supplemental table E7 (30 pack-years of smoking).

  • ¶Same clinical scenario as in online supplemental table E9 except the predicted probability was for a male worker (42.5%, labelled with ‡).