Health consequences of smoking 1-4 cigarettes per day.

Abstract

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.
Prospective study.
Oslo city and three counties in Norway.
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.
Absolute mortality and relative risks adjusted for confounding variables, of dying from ischaemic heart disease, all cancer, lung cancer, and from all causes.
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).
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.

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RESEARCH PAPER
Health consequences of smoking 1–4 cigarettes per day
K Bjartveit, A Tverdal
...............................................................................................................................
See end of article for
authors’ affiliations
.......................
Correspondence to:
Dr Kjell Bjartveit, Fridtjof
Nansens vei 24 B, N-0369
Oslo, Norway (home
address);
kjell.bjartveit@chello.no
Received 23 March 2005
Accepted 20 July 2005
.......................
Tobacco Control 2005;14:315–320. doi: 10.1136/tc.2005.011932
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.
I
s there a threshold value for daily cigarette consumption
that must be exceeded before serious health consequences
occur?
Numerous population studies have reported on a strong
dose–response relationship between cigarette consumption
and severe diseases. In most studies, however, the lowest
consumption group was set at 1–9 or 1–15 cigarettes per day.
One may argue that smokers in these groups clustered close
to the upper limit of this consumption span, and that a
threshold value might be found on a lower level.
Only a few prospective studies have reported on the
health consequences of smoking fewer than five cigarettes
per day.1–3
Our aim was 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. We report on a
Norwegian population of 23 521 men and 19 201 women,
aged 35–49 years, who in the mid 1970s were screened for
cardiovascular disease risk factors and followed throughout
2002 for deaths from ischaemic heart disease, all cancer, lung
cancer, and from all causes.
METHODS
Participants
From 1972 to 1978 screening examinations for cardiovascular
disease were undertaken in the Norwegian capital, Oslo, and
in three Norwegian counties with a mainly rural settlement.
In Oslo, all male residents aged 40–49 years were invited, and
a 7% random sample of male residents aged 20–39.4In the
counties, all male and female residents aged 35–49 years
were invited, and a 10% random sample of all residents aged
20–34.5
The screening programmes in the four areas included a
questionnaire related to cardiovascular diseases. Height,
weight, and blood pressure were measured according to an
identical protocol. A non-fasting blood sample was drawn
and serum analysed at the same laboratory for total
cholesterol, triglycerides, and glucose. Details on the screen-
ing programme have been given elsewhere.4 5
A more extensive report on this study population after 13
years of observation with relevance to smoking and mortality
has been reported previously.6
We will present pooled data for the age group 35–49 in the
Oslo study and the County study. In Oslo the attendance was
65%, in the counties 91%.
Exclusions
The following groups were excluded:
N Men and women with a history of myocardial infarction,
angina pectoris, stroke, diabetes, atherosclerosis of the
legs, treatment for hypertension, use of glyceryl trinitrate
(nitroglycerine), and symptoms indicative of angina
pectoris or atherosclerosis obliterans. These exclusions
applied to 10.2% of the attending men and 10.2% of the
attending women, leaving 36 759 men and 21 960 women.
N Ex-smokers and men smoking a pipe. The very few women
who smoked a pipe and the very few men and women who
smoked cigars are disregarded. As a result, a further
13 238 men and 2759 women were excluded.
Hence, 23 521 men and 19 201 women were left as
participants for analysis. At the time of screening, they did
not report a history related to cardiovascular disease or
diabetes, or symptoms indicative of angina pectoris or
atherosclerosis obliterans. They were daily smokers of
cigarettes only, or had never smoked daily.
Categories of daily cigarette consumption
In Oslo, the participants stated their daily cigarette con-
sumption by ticking one of the preset categories in the
questionnaire: 1–4, 5–9, 10–14, 15–19, 20–24, 25+ cigarettes.
In the counties, the attending persons reported the actual
number of cigarettes per day in a special box in the
315
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questionnaire. Here, they were allowed to give a range, such
as 10–15 cigarettes.
At the examination site, the nurses checked carefully the
questionnaire together with the attendees. In all areas,
factory made and hand rolled cigarettes had to be counted
together. The nurses were instructed that one pack of tobacco
for hand rolling (50 g) was equal to 50 cigarettes.
In our analyses, we transferred the consumption reported
by people in the counties to one of the categories used in the
Oslo questionnaire. For those who gave a range we used the
highest figure—for example, 10–15 cigarettes were cate-
gorised as 15–19, and 9–14 cigarettes as 10–14.
End points
We carried out a mortality follow up by linking our records
with the national register of causes of death, using the 11
digit personal identification number as record linkage. Each
person accrued person years from the day of screening
attendance until date of death, date of emigration, or 31
December 2002.
In addition to deaths from all causes, we studied deaths
from:
N ischaemic heart disease (ICD-8 and ICD-9: 410-414; ICD-
10: I20-I25)
N all cancer (ICD-8: 140-209; ICD-9: 140-208; ICD-10: C00-
C97)
N lung cancer (ICD-8 and ICD-9: 161-162; ICD-10: C32-
C34).
New screening in the three counties
In the three counties, a new examination was carried out
around 10 years after the baseline screening.
Eligible persons aged 35–49 years at the first screening
were re-invited; for 40.1% of the men and 68.6% of the
women who were subject to analysis from the first screening
we have information on cigarette consumption 10 years after
(10 231 men and 13 171 women). The lower male response
was mainly due to the lack of re-examination in Oslo. For
never smokers and smokers of 1–4 cigarettes at baseline we
shall give their reported consumption category 10 years later.
Statistical methods
Relative risks adjusted for confounders were estimated with
the Cox proportional hazards model.
Two sets of adjustments were made:
N Adjustments for age
N Adjustments for age, systolic blood pressure, total serum
cholesterol, serum triglycerides, physical activity during
leisure, body mass index, and body height.
Also, we ran Cox models with attained age as time variable.
The relative risk estimates were similar, less than 2%
difference from the relative risk estimates presented. The
proportional hazards assumption was assessed by visual
inspection of the plot of log minus log survival against log of
time.
RESULTS
Table 1 shows baseline characteristics of the participants. In
both sexes the duration of smoking increases by the number
of cigarettes smoked daily; smokers of 1–4 cigarettes per day
(below named ‘‘light smokers’’), however, have a distinctly
shorter history of smoking than participants with heavier
cigarette consumption. In both sexes there is an increase in
serum total cholesterol and serum triglycerides by cigarette
consumption, while there is a decrease in physical activity
during leisure. For the other variables there are only small
and inconsistent differences.
Table 2 gives the number of participants and number of
person years by cigarette consumption, and deaths from any
cause, ischaemic heart disease, all cancer, and lung cancer. In
Table 1
values, by cigarette consumption recorded at screening?
Baseline characteristics of 23521 male and 19201 female participants.* Mean
Number of cigarettes smoked daily
01–4 5–910–14 15–19 20–2425+
Males
Age (years)
Duration of smoking (years)
Systolic BP (mm Hg)
Diastolic BP (mm Hg)
Total serum cholesterol (mmol/l)
Serum triglycerides (mmol/l)
Serum glucose (mmol/l)
Physical activity leisure`
Physical activity work`
BMI (kg/m2)
Height (cm)
Females
Age (years)
Duration of smoking (years)
Systolic BP (mm Hg)
Diastolic BP (mm Hg)
Total serum cholesterol (mmol/l)
Serum triglycerides (mmol/l)
Serum glucose (mmol/l)
Physical activity leisure`
Physical activity work`
BMI (kg/m2)
Height (cm)
42.3 43.5
18.7
134.8
84.9
6.67
2.28
5.77
2.13
2.17
24.7
176.3
43.2
21.6
135.2
84.2
6.97
3.31
5.78
2.09
2.43
24.5
175.0
43.0
22.7
135.2
84.1
7.04
2.36
5.81
2.04
2.39
24.5
175.4
42.6
22.8
135.4
84.1
7.04
2.39
5.82
1.97
2.27
24.6
175.9
42.6
23.3
135.2
85.0
7.14
2.46
5.80
1.91
2.23
24.9
175.9
42.4
23.9
135.2
85.5
7.13
2.44
5.82
1.79
2.15
25.2
176.4
134.9
85.6
6.65
2.16
5.79
2.22
2.20
24.9
176.4
42.2 42.3
12.5
129.3
80.1
6.74
1.64
5.69
1.93
2.18
24.7
162.7
42.0
16.3
130.0
80.0
6.88
1.74
5.71
1.89
2.12
24.0
162.1
41.5
18.3
129.0
79.5
6.92
1.76
5.65
1.85
2.10
23.7
162.6
41.4
19.5
128.9
79.7
6.95
1.76
5.69
1.77
2.01
23.7
162.8
41.5
19.5
128.6
80.5
6.99
1.84
5.71
1.74
2.03
23.7
163.5
41.0
20.1
128.7
81.4
7.00
1.91
5.65
1.75
2.08
24.5
163.0
132.0
81.4
6.63
1.55
5.76
1.91
2.22
25.0
162.5
*Participants not reporting cardiovascular disease, diabetes or treatment for hypertension, nor symptoms of angina
pectoris and atherosclerosis obliterans.
?Number of participants within the consumption groups (see table 2).
`Physical activity during leisure and at work was graded 1–4, with 4 as the heaviest activity.
BMI, body mass index; BP, blood pressure.
316Bjartveit, Tverdal
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both sexes and all mortality groups, light smokers have
higher death rates than never smokers, the death rates
increasing with increasing cigarette consumption. Women
have lower death rates than men in all mortality and
consumption groups, the difference being most pronounced
for ischaemic heart disease. Heavy smoking women, how-
ever, have higher death rates than never smoking men.
Table 3 displays adjusted relative risks of death with never
smokers as reference, and with the two sets of adjustments
described in the section on statistical methods. Within the
various consumption groups there are only minor and
inconsistent differences between the two sets of risk figures.
Light smokers have a significantly higher relative risk of
dying from any cause, for both sexes about 1.5 times higher
than in never smokers. The same applies for relative risk of
dying from ischaemic heart disease—for both sexes, close to
three times higher. The highest relative excess rate in light
smokers is seen for lung cancer in women with a relative risk
of 5.03 (95% confidence interval 1.81 to 13.98). The
corresponding male relative risk is 2.79, but with a
confidence interval encompassing 1.0.
In both sexes and in all consumption groups, relative risk
for ischaemic heart disease is far higher than for all cancer
and for deaths from any cause, with the steepest increase
from 0 to 1–4 cigarettes per day.
On the whole, women have higher relative risks than men
of dying from ischaemic heart disease and lung cancer, but
one should keep in mind that the absolute risk is higher in
men than in women in all consumption categories.
For all mortality groups, there is a significant increasing
trend in relative risk by cigarette consumption, with the
exception of ischaemic heart disease in women.
As light smokers clearly had a shorter history of smoking
than the other consumption groups (table 1), we ran a
separate analysis for smokers in order to elucidate the impact
of this factor upon future mortality.
Table 4 presents the relative risks related to five years of
smoking. This table, and table 1, show that if duration of
smoking in the light smokers had been of the same length as
for persons in other consumption groups, their relative risk
would have been even higher than that reported in table 3,
ranging from about 7% for ischaemic heart disease to about
47% for lung cancer in women.
Table 5 shows participants who at the first screening
reported to be never-smokers, or to smoke 1–4 cigarettes
daily, and who turned up for examination 10 years later.
Of the never-smokers at baseline, 7% of the men and 5% of
the women had changed category 10 years later; 2% of both
sexes had started to smoke. Of the light smokers at baseline,
24% of the men and 20% of the women stated unchanged
daily cigarette consumption 10 years later. Higher cigarette
consumption was registered for 26% of the male and 41% of
the female light smokers, while 48% of the men and 39% of
the women had become ex-smokers or stated that they had
never smoked cigarettes daily. A few men had switched to
pipe/cigars. A dominant fraction of the light smokers with
increased consumption had moved only to the category 5–9
cigarettes per day.
DISCUSSION
Principal findings
In men and women smoking 1–4 cigarettes per day, there
was a distinct increase in risk of death from ischaemic heart
disease and from all causes. For ischaemic heart disease, the
Table 2
heart disease, all cancer, and lung cancer, number and per 100000 person years, by
number of cigarettes recorded at screening. 23521 male and 19201 female participants
aged 35–49*
Number of participants and person years; deaths from all causes, ischaemic
Number of cigarettes smoked daily
0 1–45–910–1415–1920–24 25+
Males
Number of participants
Number of person years
All causes
Number of deaths
Per 100000 person years
Ischaemic heart disease
Number of deaths
Per 100000 person years
All cancer
Number of deaths
Per 100000 person years
Lung cancer
Number of deaths
Per 100000 person years
Females
Number of participants
Number of person years
All causes
Number of deaths
Per 100000 person years
Ischaemic heart disease
Number of deaths
Per 100000 person years
All cancer
Number of deaths
Per 100000 person years
Lung cancer
Number of deaths
Per 100000 person years
8308 6272526
63464
49413401
82836
2599
61967
1119
2631021969916367 122128
1248
568
161
984
760
1198
1697
1390
1245
1503
1084
1749
499
1897
287
131
63233
367
521
427
406
490
311
502
128
487 385
446
203
40 226
356
525
430
392
473
349
563
171
650244
17
8
4 61
96
168
138
126
152
146
236
70
24 266
11077
288178
7962759
70509
3005
76158
1008
25196
477 79
2053711720 2036
956
332
98427
606
530
696
222
881
113
964
16
477786
85
29
17
83
72
102
79
104
3613
111
2
14398
579
201
46197
279
264
347
100
397
58
495
9
224442
14
5
5 43
61
65
85
3314
119
3
24 131 147
*Participants not reporting cardiovascular disease, diabetes, or treatment for hypertension, nor symptoms of
angina pectoris and atherosclerosis obliterans.
Health effects of light smoking317
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Table 3
Adjusted relative risk (RR, 95% confidence intervals) of death from all causes, ischaemic heart disease, all cancer, and lung cancer, by number of cigarettes daily recorded at
screening, with never smokers as reference. 23521 male and 19201 female participants aged 35–49*
Number of cigarettes smoked daily
Test for trend,
p
1–4
5–9
10–14
15–19
20–24
25+
Males
All causes
RR?
1.56 (1.33 to 1.84)
2.03 (1.85 to 2.22)
2.47 (2.29 to 2.65)
2.78 (2.57 to 3.00)
3.35 (3.09 to 3.64)
3.71 (3.34 to 4.11)
,0.001
RR`
1.57 (1.33 to 1.85)
1.94 (1.77 to 2.12)
2.36 (2.19 to 2.55)
2.66 (2.46 to 2.88)
3.19 (2.93 to 3.46)
3.42 (3.07 to 3.81)
,0.001
Ischaemic heart disease
RR?
2.65 (2.02 to 3.48)
2.67 (2.24 to 3.17)
3.24 (2.81 to 3.74)
3.89 (3.34 to 4.52)
4.10 (3.49 to 4.82)
4.07 (3.31 to 5.02)
,0.001
RR`
2.74 (2.07 to 3.61)
2.47 (2.06 to 2.94)
3.09 (2.67 to 2.58)
3.70 (3.17 to 4.31)
3.75 (3.18 to 4.42)
3.60 (2.91 to 4.46)
,0.001
All cancer
RR?
1.09 (0.79 to 1.50)
1.69 (1.44 to 1.98)
2.14 (1.88 to 2.42)
2.45 (2.14 to 2.81)
3.03 (2.63 to 3.49)
3.57 (2.99 to 4.26)
,0.001
RR`
1.08 (0.78 to 1.49)
1.63 (1.38 to 1.92)
2.05 (1.81 to 2.34)
2.37 (2.06 to 2.72)
2.93 (2.54 to 3.38)
3.41 (2.85 to 4.09)
,0.001
Lung cancer
RR?
2.84 (0.96 to 8.45)
11.94 (6.97 to 20.44)
17.98 (10.92 to 29.61)
20.77 (12.52 to 34.47)
33.48 (20.76 to 55.33)
38.64 (22.74 to 65.65)
,0.001
RR`
2.79 (0.94 to 8.28)
11.30 (6.59 to 19.39)
16.73 (10.14 to 27.60)
19.36 11.65 to 32.18)
31.69 (19.14 to 52.47)
36.22 (21.23 to 61.81)
,0.001
Females
All causes
RR?
1.44 (1.17 to 1.77)
1.90 (1.70 to 2.13)
2.31 (2.08 to 2.57)
3.01 (2.60 to 3.48)
3.29 (2.71 to 4.00)
2.67 (1.63 to 4.38)
,0.001
RR`
1.47 (1.19 to 1.82)
1.90 (1.69 to 2.14)
2.29 (2.01 to 2.56)
2.97 (2.55 to 3.45)
3.14 (2.56 to 3.84)
2.61 (1.59 to 4.28)
,0.001
Ischaemic heart disease
RR?
2.81 (1.67 to 4.72)
3.69 (2.69 to 5.05)
4.03 (2.97 to 5.48)
5.80 (3.92 to 8.57)
4.51 (2.52 to 8.10)
3.89 (0.96 to 15.81)
0.064
RR`
2.94 (1.75 to 4.95)
3.55 (2.57 to 4.89)
3.78 (2.75 to 5.18)
5.28 (3.50 to 7.97)
4.25 (2.35 to 7.68)
3.53 (0.87 to 14.40)
0.114
All cancer
RR?
1.11 (0.82 to 1.50)
1.44 (1.22 to 1.69)
1.87 (1.61 to 2.16)
2.18 (1.76 to 2.70)
2.73 (2.08 to 3.57)
2.44 (1.26 to 4.72)
,0.001
RR`
1.14 (0.84 to 1.55)
1.44 (1.22 to 1.71)
1.85 (1.59 to 2.16)
2.22 (1.79 to 2.76)
2.47 (1.86 to 3.29)
2.43 (1.26 to 4.71)
,0.001
Lung cancer
RR?
5.02 (1.81 to 13.93)
13.06 (7.14 to 23.87)
19.19 (10.76 to 34.21)
30.37 (16.24 to 56.81)
27.68 (13.18 to 58.11)
34.02 (9.77 to 118.44)
,0.001
RR`
5.03 (1.81 to 13.98)
11.85 (6.43 to 21.84)
17.62 (9.80 to 31.66)
28.83 15.28 to 54.38)
23.85 (11.10 to 51.25)
31.95 (9.12 to 111.96)
,0.001
*Participants not reporting cardiovascular disease, diabetes, or treatment for hypertension, nor symptoms of angina pectoris and atherosclerosis obliterans.
?Adjusted for age.
`Adjusted for age, systolic blood pressure, total serum cholesterol, serum triglycerides, physical activity during leisure, body mass index, and height.
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steepest increase was in both sexes between 0 and 1–4
cigarettes per day. Above this level, the slope was less
pronounced.
For all disease groups and cigarette consumption levels,
women had distinctly lower deaths rates than men; for
ischaemic heart disease women’s risks related to never
smokers, however, were clearly higher than in men. The
same applies to risk for lung cancer in women smoking fewer
than 20 cigarettes per day.
It may be argued that the participants’ smoking habits
could have changed essentially since the screening took
place. For example, analyses of results from the first
screening indicate a steady increase in consumption during
the first 10–20 years after starting to smoke.7This may well
have been the case, since the light smokers in this study had
a shorter history of smoking than the other consumption
groups. On the other hand, the light smokers may represent
previous heavier smokers who have cut down on consump-
tion.
Some participants who were never smokers at baseline
reported 10 years later that they were smokers, and this
biases the relative risk estimate towards the null. On the
other hand, a large proportion of light smokers had changed
smoking category, but almost as many had quit smoking as
had increased their consumption. The result of these changes
is hard to quantify. It may even differ for the specific causes,
as the dose-response relationship varies between them. In
all, we see no strong reason to believe that the relative risk
estimates for light smokers are substantially biased.
Strengths and weaknesses of the study
The strength of the study is that it includes large numbers of
both men and women who were examined according to
standardised procedures and have been observed for more
than two decades. The number of person years is 592 771 for
men and 494 334 for women. We also have information on
smoking habits 10 years later for more than half of the
participants. Furthermore, the follow up is complete.
One weakness of the study is that we have registered only
deaths from ischaemic heart disease, and not incidence, as
many other studies have. Mortality is the result of incidence
and case fatality. In the Finnmark study (part of the County
study), it was found that smoking (yes, no) was a predictor of
case fatality.8From the same study it was reported that
smoking (yes, no) was related to incidence of myocardial
infarction.9No dose-response relationship was given, how-
ever, so we cannot be sure whether light smoking has an
effect on both incidence and case fatality of myocardial
disease. For lung cancer, on the other hand, estimates of
mortality will be close to those of incidence, as the five year
relative survival rate is less than 10%.10
Relation to other studies
The results confirm and strengthen observations in three
prospective studies that have dealt with health consequences
of light smoking. In these studies risks in light smokers were
related to never smokers after adjustment for confounders
that had been registered at screening.
N In Go ¨teborg, 7495 men aged 47–55 years from the
multifactor primary prevention trial were screened in
1970–73 and followed for 11.8 years. All surviving men
who still lived in Go ¨teborg were invited to a second
screening in 1973–77 and followed for 7.1 years. In men
smoking 1–4 cigarettes per day at the first screening,
adjusted odds ratio for fatal and non-fatal myocardial
infarction was 2.8, and for deaths from all causes it was
2.0. In men with stable smoking habits at both screenings,
the corresponding adjusted odds ratios were 4.6 and 3.4.
For myocardial infarction, there was no dose–response
relationship with regard to increasing cigarette consump-
tion. The risk of light smokers’ dying from cancer was not
increased significantly.1
N Data from the US nurses’ health study were based on 12
years’ follow up (1976 through 1988). Information on
smoking habits was updated every two years by a mailed
questionnaire. A total of 117 006 women aged 30–55 years
in 1976 were included. Adjusted relative risk for women
smoking 1–4 cigarettes per day at baseline was 1.94 for
fatal and non-fatal myocardial infarction. Relative risk
increased with increasing cigarette consumption.2
N In the Copenhagen City heart study, 6505 women and
5644 men aged 30 and more underwent cardiovascular
disease screening in 1976–78, and were followed for
almost 22 years. Adjusted relative risk for women smoking
and inhaling 3–5 cigarettes per day at baseline was 2.14 for
fatal and non-fatal myocardial infarction, and 1.86 for all
cause mortality. In corresponding males the increase was
Table 4
from all causes, ischaemic heart disease, all cancer, and
lung cancer, per five years of smoking estimated from Cox
proportional hazards regression, adjusted for age and
number of cigarettes*
Relative risk (95% confidence interval) of death
MalesFemales
All causes
Ischaemic heart disease
All cancer
Lung cancer
1.09 (1.06 to 1.12)
1.07 (1.02 to 1.12)
1.14 (1.09 to 1.20)
1.29 (1.18 to 1.41)
1.12 (1.08 to 1.18)
1.07 (0.96 to 1.19)
1.13 (1.06 to 1.21)
1.47 (1.26 to 1.71)
*Participants not reporting cardiovascular disease, diabetes, or treatment
for hypertension, nor symptoms of angina pectoris and atherosclerosis
obliterans.
Table 5
women reporting at baseline never to have smoked, and 224 men and 552 women reporting at baseline a consumption of 1–4
cigarettes per day. Number of persons, age 35–49 at baseline*
Smoking habits 10 years after baseline screening in persons who attended both examinations. 3774 men and 7591
Category at baseline
Categories of smoking 10 years after baseline screening
Never
smokedEx-smokers
1–4
cigs
5–9
cigs
10–14
cigs
15–19
cigs
20–24
cigs
25+
cigs
Pipe
only
Pipe +
cigars
Total number
of persons
Males
Never smoked
1–4 cigs
3523177
93
18
53
16
44
14
13
9
2
3
0
2
0
7
3
5
1
3774
22415
Females
Never smoked
1–4 cigs
7239 163
144
58
113
69
179
42
38
108
3
2
2
0
0
0
0
7591
552712
*Participants not reporting cardiovascular disease, diabetes, or treatment for hypertension, nor symptoms of angina pectoris and atherosclerosis obliterans.
Health effects of light smoking319
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