Health consequences of smoking 1-4 cigarettes per day.

OBJECTIVES

To determine the risk in men and women smoking 1-4 cigarettes per day of dying from specified smoking related diseases and from any cause.

DESIGN

Prospective study.

SETTING

Oslo city and three counties in Norway.

PARTICIPANTS

23,521 men and 19,201 women, aged 35-49 years, screened for cardiovascular disease risk factors in the mid 1970s and followed throughout 2002.

OUTCOMES

Absolute mortality and relative risks adjusted for confounding variables, of dying from ischaemic heart disease, all cancer, lung cancer, and from all causes.

RESULTS

Adjusted relative risk (95% confidence interval) in smokers of 1-4 cigarettes per day, with never smokers as reference, of dying from ischaemic heart disease was 2.74 (2.07 to 3.61) in men and 2.94 (1.75 to 4.95) in women. The corresponding figures for all cancer were 1.08 (0.78 to 1.49) and 1.14 (0.84 to 1.55), for lung cancer 2.79 (0.94 to 8.28) and 5.03 (1.81 to 13.98), and for any cause 1.57 (1.33 to 1.85) and 1.47 (1.19 to 1.82).

CONCLUSIONS

In both sexes, smoking 1-4 cigarettes per day was associated with a significantly higher risk of dying from ischaemic heart disease and from all causes, and from lung cancer in women. Smoking control policymakers and health educators should emphasise more strongly that light smokers also endanger their health.