Maturitas, I (1979) 171-173 0 Elsevier/North-Holland Biomedical Press
THE EFFECT
OF SMOKING ON MENOPAUSAL
171
AGE
OLOF LINDQUIST and CALLE BENGTSSON Department
of Medicine,
University of Giiteborg, Giiteborg, Sweden
(Received 25 July 1978, accepted 6 October 1978)
A comprehensive population study of women in Giiteborg, Sweden was carried out in 1968-1969. Altogether 1462 women in five age strata were studied. The age stratum 50 comprised about the same number of postmenopausal women (n = 161) and women who still menstruated (n = 168). A comparison could, therefore, be made between still menstruating and postmenopausal women of almost identical age. In postmenopausal SO-yr-old women 50% were smokers compared to 26% in 50-yr-old women who still menstruated. The difference was highly significant. Almost all the postmenopausal women had been smokers for many years, which means that they did not start smoking as a consequence of the menopause. It thus seemed that an earlier menopause was a consequence of smoking. The difference could not or only to a small extent be explained by other factors such as differences in body weight between smokers and non-smokers. (Key words: Menopause, Menopausal age, Smoking, Population study)
INTRODUCTION An earlier menopausal age has been reported in female smokers compared to female non-smokers [l-4]. This association between an early menopause and smoking has been considered by us to be so interesting that we decided to further study this question in a population sample of women in an age strata near the mean menopausal age. The question is of particular interest as there also seems to be an association between precocious menopause and myocardial infarction and between smoking and myocardial infarction as found by other investigators as well as by us [5]. It is thus possible that an association between early menopause and myocardial infarction could be explained by an increased number of smokers among women with precocious menopause. MATERIAL AND METHODS
A population study of women was carried out in Gb;teborg, Sweden during the years 1968-1969 [6]. Altogether 1462 women in the age strata 38, 46, 50, 54 and 60 were studied. The participation rate was 90.1%. Information about menstrual state and smoking habits was obtained by questionnaire Correspondence to: Dr. Olof Lindquist, Department of Medicine, ostra sjukhuset, S-416 85 GSteborg, Sweden.
172 TABLE I Number of smokers in premenopausal
and postmenopausal
50-yr-old women.
Postmenopausal
Premenopausal Total
Smokers
n
n
168
43
Statistical significance
Total
Smokers
%
n
n
%
26
161
80
50
P < 0.001
and interview. Women who had menstruated during the last 2 mth were defined as premenopausal. Those were defined as postmenopausal who had not had menstruations during the last 5 mth, as very few women were found to start menstruating again if the period of amenorrhoea had lasted for 6 mth or longer [7]. We have paid special attention to the 50-yr-old women (mean age at the time of the examination 50.55 yr, standard deviation 0.20 yr). This age stratum consisted of 398 women. Thirty five of these women had stopped menstruating as a consequence of surgery. They are excluded in the present analysis. Thirty-four women who had not had any menstruations for 2 mth or more but within the last 5 mth are also excluded, as it is considered uncertain whether they had stopped menstruating or not. The numbers of still menstruating or premenopausal women (n = 168) and spontaneously postmenopausal women (n = 161) were found to be similar in the group of 50-yr-old women. In the present paper only data on women aged 50 are presented. RESULTS
As seen from Table I there are more smokers in the postmenopausal 50-yr-old women than in those 50-yr-old women who still menstruated. The difference was statistically significant (chi-square test). No difference was found between heavy smokers (>I.5 cigarettes per day) and other smokers.
TABLE II Duration smokers.
of smoking
in premenopausal
Duration of smoking (yr)
THE EFFECT
OF SMOKING ON MENOPAUSAL
171
AGE
OLOF LINDQUIST and CALLE BENGTSSON Department
of Medicine,
University of Giiteborg, Giiteborg, Sweden
(Received 25 July 1978, accepted 6 October 1978)
A comprehensive population study of women in Giiteborg, Sweden was carried out in 1968-1969. Altogether 1462 women in five age strata were studied. The age stratum 50 comprised about the same number of postmenopausal women (n = 161) and women who still menstruated (n = 168). A comparison could, therefore, be made between still menstruating and postmenopausal women of almost identical age. In postmenopausal SO-yr-old women 50% were smokers compared to 26% in 50-yr-old women who still menstruated. The difference was highly significant. Almost all the postmenopausal women had been smokers for many years, which means that they did not start smoking as a consequence of the menopause. It thus seemed that an earlier menopause was a consequence of smoking. The difference could not or only to a small extent be explained by other factors such as differences in body weight between smokers and non-smokers. (Key words: Menopause, Menopausal age, Smoking, Population study)
INTRODUCTION An earlier menopausal age has been reported in female smokers compared to female non-smokers [l-4]. This association between an early menopause and smoking has been considered by us to be so interesting that we decided to further study this question in a population sample of women in an age strata near the mean menopausal age. The question is of particular interest as there also seems to be an association between precocious menopause and myocardial infarction and between smoking and myocardial infarction as found by other investigators as well as by us [5]. It is thus possible that an association between early menopause and myocardial infarction could be explained by an increased number of smokers among women with precocious menopause. MATERIAL AND METHODS
A population study of women was carried out in Gb;teborg, Sweden during the years 1968-1969 [6]. Altogether 1462 women in the age strata 38, 46, 50, 54 and 60 were studied. The participation rate was 90.1%. Information about menstrual state and smoking habits was obtained by questionnaire Correspondence to: Dr. Olof Lindquist, Department of Medicine, ostra sjukhuset, S-416 85 GSteborg, Sweden.
172 TABLE I Number of smokers in premenopausal
and postmenopausal
50-yr-old women.
Postmenopausal
Premenopausal Total
Smokers
n
n
168
43
Statistical significance
Total
Smokers
%
n
n
%
26
161
80
50
P < 0.001
and interview. Women who had menstruated during the last 2 mth were defined as premenopausal. Those were defined as postmenopausal who had not had menstruations during the last 5 mth, as very few women were found to start menstruating again if the period of amenorrhoea had lasted for 6 mth or longer [7]. We have paid special attention to the 50-yr-old women (mean age at the time of the examination 50.55 yr, standard deviation 0.20 yr). This age stratum consisted of 398 women. Thirty five of these women had stopped menstruating as a consequence of surgery. They are excluded in the present analysis. Thirty-four women who had not had any menstruations for 2 mth or more but within the last 5 mth are also excluded, as it is considered uncertain whether they had stopped menstruating or not. The numbers of still menstruating or premenopausal women (n = 168) and spontaneously postmenopausal women (n = 161) were found to be similar in the group of 50-yr-old women. In the present paper only data on women aged 50 are presented. RESULTS
As seen from Table I there are more smokers in the postmenopausal 50-yr-old women than in those 50-yr-old women who still menstruated. The difference was statistically significant (chi-square test). No difference was found between heavy smokers (>I.5 cigarettes per day) and other smokers.
TABLE II Duration smokers.
of smoking
in premenopausal
Duration of smoking (yr)
