The impact of smoking in Chinese older persons in Hong Kong: a life table analysis

Abstract

Background

Smoking is a well known risk factor for increased mortality. Although some smokers

may survive to older ages, they often suffer from poor health and impaired quality of

life (QoL) because of chronic diseases. The construct of health-adjusted life

expectancy (HALE) combines mortality and the subjective perception of health-related

quality of life (HRQoL) into a single index. The impact of smoking on HALE might

be useful information for encouraging smokers to quit or young people not to start

smoking. However, scarce information is available, particularly from Chinese

populations, on how smoking affects HALE.

Aims

The study aimed to determine the impact of smoking on HALE among Chinese people

aged 65 years or over in Hong Kong who had enrolled in an Elderly Health Centre

(EHC).

Methods

Data on a cohort of 66,820 people enrolled in EHCs of the Department of Health during

1998 to 2001, were used. These were supplemented by a follow-up telephone survey

of a stratified (for smoking status) sample of 2,441 from the whole EHC database,

which included more recent enrollees. Two measures of HALE were used: (1) based

on a simple measure of perceived health and (2) based on quality-adjusted life years

(QALYs) estimated. The first measure had been included in the EHC database but

current information was obtained by telephone for each year of follow-up. The second

measure was only available from the survey. Multi-state life tables and Sullivan?s

method were employed to investigate HALEs among current, ex and never smokers.

The yearly transition rates between health statuses were calculated using the existing

data on self-assessed health and supplemented by the survey data. Utility scores for

calculation of QALYs used a local estimation equation for the SF-12.

Results

Men at age 65 who had never smoked could expect to live a further 20 years and

women a further 22 years. This was around 3-5 years more than for current or

ex-smokers. Both male and female never smokers at age 65 could expect to be in a

good QoL for 16 of those future years. Those still smoking at age 65 could expect 3-4

fewer years in a good QoL. People who had quit smoking before age 65 gained about

one more year in good health compared with continuing smokers.

Conclusions

It has already been estimated that smokers of all ages lose up to about 10 years of life

due to smoking. However, the longer they survive, the lower the difference in

mortality between ever smoker and never smokers. This study shows that, for those

who were still alive at age 65 years in this cohort, smoking was still detrimental to their

survival and to their QoL, especially if they were still smoking at that age. Results for

males and females were similar. Therefore, even if a smoker does not die prematurely,

their HRQoL is still affected and a never smoker will have not only longer life but more

life years in good health than an ever smoker. Stopping smoking at an earlier age

might gain back some HRQoL.