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.

Olaf Scheel and Johannes Heimbeck: their contribution to understanding the pathogenesis and prevention of tuberculosis

From 1924 onwards, mandatory tuberculin testing (von Pirquet's method) was introduced for student nurses on entry to the Ullevaal Hospital School of Nursing, Oslo. The chief physician of the hospital's Department IX, Olaf Scheel, was responsible for this measure. In 1927, his deputy Johannes Heimbeck showed that about half of the students were not infected at the time of entry, a conclusion that was in fundamental conflict with the prevailing view that nearly all tuberculous infection occurred in childhood. Virtually all tuberculin-negative student nurses, however, became infected during their 3-year training. These findings changed our understanding of the pathogenesis of tuberculosis. BCG vaccination had recently been introduced by Calmette. From 1927 onwards Heimbeck offered BCG vaccination to tuberculin-negative student nurses, while Scheel undertook a similar project among medical students. The two projects continued until respectively 1936 and 1939. Long-term follow-up of both groups demonstrated a protective effect of about 80% in those accepting vaccination. Calmette had given the vaccine per os to new-born babies. Heimbeck and Scheel pioneered giving the vaccine via injection and to adults. These projects have been criticised for being based on voluntary inclusion and not being conducted as randomised control trials. The results were so convincing, however, that they led to the launch of the Norwegian BCG programme shortly after World War II. Scheel and Heimbeck' efforts were also of great importance for the use of the BCG vaccine in other countries.

[Olaf Scheel and Johannes Heimbeck and their work with the BCG vaccine]

From 1924 and onwards, obligatory tuberculin test (Pirquet's method) was introduced at the time when student nurses commenced their training at Ullevål Hospital's school of nursing. Chief physician of the hospital's department IX, Olaf Scheel, was responsible for this measure. In 1927, his deputy, Johannes Heimbeck, showed that about half of the students were not infected at the time of school entrance. This conclusion was in fundamental conflict with the prevailing view that nearly all tuberculous infection took place in childhood. Virtually all Pirquet-negative student nurses were, however, infected in the course of the three-year training period. BCG vaccine had recently been introduced by Calmette. From 1927 onwards, Heimbeck offered BCG vaccination to the Pirquet-negative student nurses, while Scheel undertook a similar project among medical students. The two projects went on to 1936 and 1939. Follow up of both groups demonstrated a protective effect of about 80 per cent. Calmette had given the vaccine per os to new-born babies. Heimbeck and Scheel pioneered by giving the vaccine by injection and to adults. The projects have been criticised for being based on voluntary attendance and not conducted as randomised control trials. The results, however, were so convincing that they became decisive for the Norwegian BCG programme that was launched shortly after the Second World War. The efforts by Scheel and Heimbeck were also of great importance to the use of BCG vaccine in other countries.

Diagnostic quality in hysterosalpingography. Comparison between iodixanol and iotrolan

PURPOSE

To compare the diagnostic quality and adverse events of the water-soluble, non-ionic, iso-osmolar, dimeric contrast media iodixanol and iotrolan in hysterosalpingography (HSG).

MATERIAL AND METHODS

One hundred and twenty patients participated in a double-blind randomized parallel-group phase-III study. Questionnaires and patient interviews were used. Diagnostic quality was assessed using a visual analogue scale and the quality in specific regions was rated using a categorical scale.

RESULTS

Overall diagnostic quality was equal for the two groups. There was no statistically significant difference between the two groups in diagnostic quality in the specific regions of interest. No differences between the contrast media were found with regard to adverse events.

CONCLUSION

Both contrast media provided images of high diagnostic quality in HSG.

Ex-smokers and risk of hip fracture

OBJECTIVES

The purpose of this study was to examine the reversibility of the effect of smoking on hip fracture incidence rates.

METHODS

A 3-year follow-up cohort study was conducted involving 35,767 adults 50 years of age or older. Of these individuals, 421 suffered a hip fracture.

RESULTS

Among participants less than 75 years of age, the relative risk (RR) of hip fracture was elevated for ex-smokers, even for those who had quit smoking more than 5 years previously (men: RR = 4.4, 95% confidence interval [CI] = 1.2, 15.3; women: RR = 1.3, 95% CI = 0.6, 3.0), but was not as high as that for current smokers (men: RR = 5.0, 95% CI = 1.5, 16.9; women: RR = 1.9, 95% CI = 1.2, 3.1).

CONCLUSIONS

The effect of smoking on risk of hip fracture was not reversed completely 5 years after smoking cessation.

A comparison of a non-ionic dimer, iodixanol with a non-ionic monomer, iohexol in low dose intravenous urography

A prospective, double-blind study of 392 patients randomized into four groups was performed to establish whether diagnostic intravenous urograms could be obtained with a lower dose of iodine when using the dimeric, non-ionic contrast medium iodixanol compared with the monomeric, non-ionic iohexol. Patients received iodixanol or iohexol containing either 9 or 12 g of iodine (gI). The primary parameter was the diagnostic quality of the 6 min film, assessed in a blinded fashion, by consensus, by four radiologists. Iodixanol at both doses was diagnostic in over 90% of cases. Iohexol was only diagnostic in 74% (9 gI) and 81.8% (12 gI). Pairwise comparisons revealed that iodixanol 9 gI was significantly better than both iohexol 9 gI (p = 0.0005) and 12 gI (p = 0.014). No significant difference was present for different doses within the same contrast medium group. Iodixanol resulted in poorer bladder distension than iohexol. Iodixanol caused significantly less discomfort than iohexol.

[Cardiovascular risk factors in Oslo, Sogn and Fjordane and Finnmark. Study of 40-year old subjects in Oslo 1981-88]

Cardiovascular risk factor levels among 40-year olds in Oslo were studied from the early 1970s until the late 1980s. Comparison has been made with similar data for the same period from two other regions in the country. The serum cholesterol level in men decreased from 6.3 mmol/l in 1972-73 to 5.9 mmol/l in 1985-88 and the proportion of men who smoked on a daily basis decreased from 51.8% to 40.8%. The proportion of female smokers increased from 37.4% in 1981-84 to 39.5% in 1985-88. There was a decrease in systolic blood pressure among men from 1972-73 to 1985-88. From 1981-84 to 1985-88 there was a minor increase for both sexes in the proportion of physically inactive for both sexes or those with a body mass index > 30. Prior to 1980 cardiovascular risk factors were most favourable in Sogn og Fjordane, and least favourable in Finnmark, with men from Oslo positioned somewhere in between these counties. With the exception of women's smoking habits and, for both sexes, the degree of physical activity, people living in Oslo in 1985-88 had a more favourable risk factor status than those in Sogn og Fjordane in 1985 and in Finnmark in 1987. Despite a degree of uncertainty because of methodological issues, the results indicate a reduction in risk factors of cardiovascular disease among men in Oslo during the 15 years covered by the study.

Renal CT after intravenous injection of nonionic dimeric or nonionic monomeric contrast media in healthy volunteers

PURPOSE

To establish and compare time-density curves of the aorta, vena cava and renal cortex, medulla and pelvis after injection of the nonionic dimer iodixanol or the nonionic monomer iopromide contrast media.

MATERIAL AND METHODS

In 36 healthy volunteers CT at the renal hilus was performed at regular intervals before and until 30 min after injection of 13.5 g I iodixanol or 15.0 g I iopromide. The density of the renal cortex, medulla, pelvis, aorta and inferior caval vein was measured.

RESULTS

With injection of the 10% lower iodine dose in the iodixanol group, the profiles of the CT time-density curves were similar for all regions except for the renal pelvis. For the renal pelvis, significantly higher density values were obtained for the iodixanol group up to 10 min after injection.

CONCLUSION

Although the present study shows that a lower iodine dose is needed for a dimeric compared to a monomeric nonionic contrast medium to obtain similar time-density curves, more studies are needed to establish the clinical importance of this for urography.

Iopentol (Imagopaque 300 and 350) compared with iohexol (Omnipaque 300 and 350) in cerebral and aortic arch angiography. A clinical trial assessing adverse events and diagnostic information

The safety of the non-ionic contrast medium iopentol (Imagopaque, Nycomed Imaging AS, Oslo, Norway) when used in cerebral angiography and aortic arch angiography, was the focus of this investigation. Overall quality of visualization and changes in heart rate and blood pressure were, however, also assessed. In total, 39 patients were injected with iopentol and 41 patients with the comparative contrast medium, iohexol (Omnipaque, Nycomed Imaging AS, Oslo, Norway). Two patients (5%) in each group reported contrast-related adverse events other than a sensation of heat, while three patients in the iopentol group and four in the iohexol group reported procedure-related adverse events. A sensation of heat was reported by 21 patients (54%) in the iopentol group, and by 20 patients (49%) in the iohexol group. There were no clinically relevant changes in heart rate or blood pressure. The diagnostic information obtained was of sufficient or excellent quality for all patients. Statistical analyses did not indicate any significant difference between the two contrast media. Iopentol was well suited for cerebral and aortic arch angiography, comparable to iohexol regarding safety and efficacy.

Iopentol (Imagopaque 250) compared with diatrizoate (Urografin 219) in endoscopic retrograde cholangio-pancreatography (ERCP). A clinical trial assessing safety (adverse events and S-pancreatic iso-amylase) and diagnostic information (VAS)

The efficacy and safety of the non-ionic contrast medium iopentol, 250 mg I/ml (Imagopaque, Nycomed Imaging AS, Oslo, Norway) were evaluated and compared to those of the ionic contrast medium diatrizoate 219 mg I/ml (Urografin, Schering AG, Berlin, Germany). The trial was carried out as a randomized, double-blind comparative two-group study. One hundred and sixteen patients completed the study: 59 received iopentol and 57 received diatrizoate, the contrast medium used according to routine hospital procedure for ERCP. Demographic data and details of the ERCP procedure were comparable for the two contrast medium groups. Safety was assessed by monitoring serum pancreatic iso-amylase and by recording adverse events. Efficacy was evaluated through assessment of the diagnostic information and the quality of radiographs. Twenty-one of the patients receiving iopentol and 27 of the patients receiving diatrizoate reported adverse events during the ERCP procedure. Pain was the kind of procedure-related event most frequently reported. Three patients experienced serious adverse events with a fatal outcome 2, 10 and 12 days after the ERCP procedure, respectively. The principal investigator concluded for all three serious adverse events that any causal relationship with the contrast medium injected was unlikely. A mean change in serum pancreatic iso-amylase after contrast medium injection was noted in both contrast medium groups. However, statistical analysis did not show any significant difference between mean changes for the two groups. The efficacy results, both in terms of diagnostic information and quality of radiographic visualisation, were comparable for the two contrast media. In conclusion, the study did not show any statistically significant differences between the two contrast media as regards safety or efficacy in ERCP.

[Tuberculosis trends in Norway--has the decline stopped?]

The aim of the study was to present the trend as regards tuberculosis in Norway since 1950, on the basis of data on incidence and mortality in the total population and infection rate among pupils leaving primary school. The decline in incidence continued until the late 1980s. While the decline was 11% per year during the period 1950-74, it has been slower in recent years. In 1990-92 the incidence level was somewhat higher than in 1989, but figures for 1993-94 indicate a new decline. Mortality declined more slowly after the mid-1970s; a similar trend is found for prevalence of infection among pupils. The incidence is among the lowest in Europe. The proportion of cases among immigrants increased gradually from 4% in 1977 to 40% in 1993. Among the Norwegian-born population the incidence rate of infectious pulmonary tuberculosis has shown a steady decline, also during the last decades. Norwegian-born cases are mainly elderly persons infected many decades ago. New infection is probably rare, and the proportion of infected persons is gradually declining.

Prevalence of known and previously unknown diabetes mellitus and impaired glucose tolerance in an adult Norwegian population. Indications of an increasing diabetes prevalence. The Nord-Trøndelag Diabetes Study

OBJECTIVE

To establish the prevalence of known and undiagnosed diabetes mellitus and impaired glucose tolerance in a representative Norwegian adult population according to the 1980 World Health Organization Expert Committee diagnostic criteria.

DESIGN

Screening survey applying questionnaire and non-fasting blood glucose followed by a fasting and an oral glucose tolerance test.

SETTING

The county of Nord-Trøndelag, Norway, 1984-86.

SUBJECTS

All inhabitants aged > or = 20 years (85,100); 90.3% participated. For previously unknown diabetes: all inhabitants > or = 40 years (53,001)--participation rate 84.7%.

MAIN OUTCOME MEASURE

Prevalence.

RESULTS

The prevalence of previously known diabetes was 2.6% in men and 3.2% in women. Total diabetes prevalence > or = 40 years was 4.8% in men and 5.6% in women. The prevalence increased continuously with age until 90 years. One patient in five was previously undiagnosed. Impaired glucose tolerance in those with an abnormal non-fasting value was rare; only 0.9% in men and 0.2% in women. The prevalence of known diabetes was three times higher than 20-30 years ago and four times higher than 50 years ago. Except for known diabetes in the very old the prevalence corresponded well with recent Nordic studies.

IMPLICATIONS

The present diabetes prevalence was so high that interested general practitioners will get sufficient experience in follow-up of diabetic patients to facilitate a good quality of the care.

Interaction between current smoking, leanness, and physical inactivity in the prediction of hip fracture

To study the association between smoking habits and the incidence of hip fracture, adjusted for leanness and physical inactivity, a cohort study with 3 years follow-up was conducted. Subjects were 34,856 adults aged 50 years or older who attended a health screening in Nord-Trøndelag County in Norway in 1984-1986 (91% of eligible subjects in 1986, n = 38,356). Of these, 421 suffered a hip fracture during the years 1986-1989. Using Cox regression models, the relative risk (with 95% confidence interval) of suffering a hip fracture for female smokers versus nonsmokers was 1.5 (1.0-2.4). These results refer to females when the female body mass index (BMI) was set at 25 kg/m2 in the female model (the mean BMI for the smoking female population in this study). Among thinner females, however, smoking had a much stronger effect. For instance, if the female BMI was set at 20 kg/m2, the relative risk was 3.0 (1.8-5.0). The relative risk of hip fracture for male smokers versus nonsmokers was 1.8 (1.2-2.9) irrespective of BMI. Smoking is associated with incidence of hip fracture in both sexes and also after adjusting for body mass index and physical inactivity (the effect of physical inactivity was adjusted for self-reported ill health because ill health was included in the model). For lean females, the association with current smoking was large, as large as if they added 10 years to their age.

Iodixanol in intravenous urography: a comparison of iodixanol 270 mgI/ml, iodixanol 320 mgI/ml and iopamidol 300 mgI/ml (NIOPAM)

The first European trial of iodixanol (Nycomed Imaging AS) in adult intravenous urography is reported. Iodixanol is a new non-ionic, dimeric contrast medium of low osmolality. A double-blind, randomized, three group parallel study comparing iodixanol 270 mgI/ml, iodixanol 320 mgI/ml and iopamidol 300 mgI/ml (Niopam) was undertaken. A total of 173 of 180 patients entered completed the trial. Efficacy was evaluated with regard to overall diagnostic information and pyelographic density 5 min after contrast medium administration. Efficacy was found to increase with increasing iodine concentration, with no significant difference between the three contrast media. The incidence of adverse events was low, with no significant difference between the groups. Discomfort occurred less frequently with iodixanol than with iopamidol. We conclude that iodixanol is a safe and efficacious contrast medium for use in intravenous urography.

Mortality in relation to smoking history: 13 years' follow-up of 68,000 Norwegian men and women 35-49 years

A total of 44,290 men and 24,535 women aged 35-49 have been followed with respect to different causes of death during 13.3 years on average. A detailed history of smoking, together with other important risk factors, were recorded in a standardized way. Compared with the classical American and British studies, the excess mortality for the smokers was largely the same for the majority of causes. The exceptions were cerebrovascular mortality and suicides and accidents, which were more strongly related to smoking in this study. Furthermore, men who smoked only pipe, had nearly the same coronary heart disease mortality as men who smoked only cigarettes. The same applies to lung cancer mortality. Among men who had quit cigarette smoking, the coronary heart disease mortality decreased with time since quitting to almost the level of the never cigarette smokers after 5 years or more.

[Cardiovascular screenings in Norwegian counties. Trends in risk pattern during the period 1985-90 among persons aged 40-42 in 4 counties]

In 1985-90, two screenings for cardiovascular disease risk factors were carried out with an interval of three years in four Norwegian counties. All residents aged 40-42 were invited to both screening rounds, and certain subgroups from the first round were re-invited to the second round. Compared with the score attained by the first generation, the total mean risk score for myocardial infarction achieved by the second generation was 19% lower in males, and 15.5% lower in females. The main cause of this reduction was lower serum cholesterol level. Based on results from the subgroups, the estimated mean risk score for the total male cohort from the first round had decreased by 10% at the rescreening three years later. It is concluded that the results indicate a continued, and perhaps accelerated, decrease in coronary heart disease mortality, as new generations populate the age groups where this disease is more prevalent. The screenings were part of a prevention programme, and it is reasonable to assume that the efforts by the primary health care services contributed to the improvement.

[Cardiovascular screenings in Norwegian counties. Background and implementation. Status of risk pattern during the period 1986-90 among persons aged 40-42 years in 14 counties]

Screening for cardiovascular disease risk factors was carried out in 14 of Norway's 19 counties in 1986-1990 as part of a prevention programme. All residents aged 40-42 were invited. The attendance was 73.5% for males and 82.6% for females. A total of 87,761 persons were examined. The screening included determination of serum cholesterol and triglycerides, measurement of blood pressure, height and weight, and filling in a questionnaire. Mean serum cholesterol was 5.90 mmol/l for males and 5.55 mmol/l for females, mean systolic blood pressure 135.3 and 126.1 mm, and prevalence of daily smoking 43.5 and 41.8%. The risk factor levels in the 341 municipalities of the 14 counties are shown cartographically. For both sexes, the highest risk score was found in the northernmost county, the lowest in southern counties. The risk was also relatively high in some rural areas in southern Norway. By geographical area there was a strong correlation between the risk factor levels of the two sexes, and a less consistent but marked correlation between the means for the various risk factors.

Coffee consumption and death from coronary heart disease in middle aged Norwegian men and women

OBJECTIVE

To study the association between number of cups of coffee consumed per day and coronary death when taking other major coronary risk factors into account.

DESIGN

Men and women attending screening and followed up for a mean of 6.4 years.

SETTING

Cardiovascular survey performed by ambulatory teams from the National Health Screening Service in Norway.

PARTICIPANTS

All middle aged people in three counties: 19,398 men and 19,166 women aged 35-54 years who reported neither cardiovascular disease or diabetes nor symptoms of angina pectoris or intermittent claudication.

MAIN OUTCOME MEASURE

Predictive value of number of cups of coffee consumed per day.

RESULTS

At initial screening total serum cholesterol concentration, high density lipoprotein cholesterol concentration, blood pressure, height, and weight were measured and self reported information about smoking history, physical activity, and coffee drinking habits was recorded. Altogether 168 men and 16 women died of coronary heart disease during follow up. Mean cholesterol concentrations for men and women were almost identical and increased from the lowest to highest coffee consumption group (13.1% and 10.9% respectively). With the proportional hazards model and adjustment for age, total serum and high density lipoprotein cholesterol concentrations, systolic blood pressure, and number of cigarettes per day the coefficient for coffee corresponded to a relative risk between nine or more cups of coffee and less than one cup of 2.2 (95% confidence interval 1.1 to 4.5) for men and 5.1 (0.4 to 60.3) for women. For men the relative risk varied among the three counties.

CONCLUSIONS

Coffee may affect mortality from coronary heart disease over and above its effect in raising cholesterol concentrations.

Serum triglycerides as an independent risk factor for death from coronary heart disease in middle-aged Norwegian men

The relation between nonfasting serum triglycerides and death from coronary heart disease was studied in 37,546 men aged 35-49 years who were examined during 1972-1977 in four counties in Norway. During an average follow-up period of nine years, 369 deaths from coronary heart disease occurred. In univariate analysis, log(triglycerides) were a weak, but statistically significant predictor of coronary death in the age groups 40-44 and 45-49 years. Within-area analysis showed that a high triglyceride area represented no extreme. When other coronary risk factors were adjusted for, log(triglycerides) remained a significant independent predictor at ages 45-49 years and at higher levels of serum cholesterol. The predictive strength of serum cholesterol was largely the same whether log(triglycerides) were taken into account or not, whereas the predictive strength of log(triglycerides) depended on whether serum cholesterol was accounted for. The strength of coronary death prediction of the logarithm of serum triglycerides was hardly greater than might be explained by the fact that triglycerides are an indicator of the usual cholesterol level of the subject.

Notification of tuberculosis in the south-west health region of Norway: incidence and trends

A survey of tuberculosis notification from the south-west health region of Norway showed a decrease from 17.7 cases of tuberculosis per 100,000 population during 1969-1973 to 12.3 cases per 100,000 during 1979-1983. The notification rate linearly increased with age from the age of 20 years on a logarithmic scale. The downward trend in notification was less marked in the last 5-year period compared with the first 5-year period probably due to changes in notification procedures in 1976, an epidemic of tuberculosis in the health region and on oil platforms in the North Sea in 1980 and an increased immigration of people from areas with high incidence of tuberculosis. Tuberculosis of the extrathoracic lymph nodes was during 1979-1983 the most frequent location of non-respiratory tuberculosis.

Effect of intervention on coronary heart disease risk factors in some Norwegian counties

Since 1974, a cardiovascular disease screening and intervention program has been carried out in three of the 19 Norwegian counties, namely Finnmark, Sogn og Fjordane, and Oppland. The program strategy was designed to affect both the general population and a defined high-risk group. Procedures were based upon the organization and implementation already well in place through the national tuberculosis prevention program established in the 1940s. The National Health Screening Service performed two screenings, three to five years apart, to identify cardiovascular disease risk factors in all county residents aged 35 to 49 years (age at first screening), and in representative samples of residents aged 20 to 34 years. After each screening, the local general practitioners and public health nurses were responsible for follow-up and intervention against risk factors among defined high-risk persons, as well as for intensified health education in the general population. Between the first and second screenings, a substantial reduction occurred in the level of smoking and in the mean level of total serum cholesterol. A risk score, including values for cholesterol, systolic blood pressure, and cigarette smoking, showed a reduction of approximately 20 percent (in males aged 35 to 49 years). A more detailed analysis of the Finnmark data revealed that the mean reduction was mainly due to a marked reduction within the high-risk group. This occurred particularly with mean cholesterol levels. Since the screening and intervention program was based upon the model established by the Oslo Study, it is reasonable to expect the county program to have had a similar preventive effect. This question will be addressed in future studies.

Intervention on cardiovascular disease risk factors in Finnmark county: changes after a period of three years. The Cardiovascular Disease Study in Finnmark County, Norway

In Finnmark county in Norway, 12 329 males and females aged 20-49 years participated in two screening examinations with an interval of 3 years. The primary health service attempted, without receiving any extra resources, to reduce the risk of cardiovascular disease by means of a personal intervention programme among high-risk individuals and a health education programme directed at all residents in the county. During these 3 years the serum total-cholesterol (cross-sectionally) level decreased on average by about 0.3 mmol/l due to: firstly, a decrease among persons recommended a follow-up examination and secondly a decrease among household members of persons followed-up. The effect of a recommendation to attend a follow-up examination because of high blood pressure was doubtful. Cigarette consumption (cross-sectionally) decreased 12% for males and 4% for females. The joint decrease (improvement) in risk factors indicates a possible health benefit of about 20%, calculated in terms of myocardial infarction over 10 years.

Smoking habits among Norwegian doctors 1974

In the spring of 1974 a representative sample (N = 1200) of all doctors in Norway (6 000) received a mailed questionnaire regarding past and present smoking habits. Close to 95% responded. Among late responders there was a disproportionately high number of smokers. As compared with the general population, both male and female doctors constitute a small proportion of daily smokers and a large proportion of exsmokers. The greatest contrasts are observed in the younger age groups. The percentage of daily smokers in this crossectional study on the medical profession is approximately 50% lower than that found in the 1952--53 study on Norwegian doctors. There is also a shift away from cigarette smoking toward the use of pipe and cigars, which is not found in the general population. Answers to questions regarding reasons for quitting as well as certain attitudinal indicators show that the doctors' reduction in smoking is related to their professional involvement and high level of knowledge concerning the health consequences of smoking.

Some evidence of the efficacy of mass BCG vaccination

To assess the efficacy of mass BCG programmes the authors have made a comparative analysis of age-specific trends in the incidence of active tuberculosis in the three Scandinavian countries, where mass vaccination of specific age-groups has been carried out since the late 1940s, and two states of the USA (upstate New York and Ohio), where mass BCG campaigns have never been conducted.In the three Scandinavian countries a markedly more favourable incidence trend was observed in the age-groups following the first inoculation-as compared with other age-groups in the same country and with corresponding age-groups in the other countries where a different BCG programme, or no programme at all, has been applied. The authors consider that these observed differences in incidence trends reflect the influence of BCG vaccination and, on this assumption, have attempted to estimate the primary effect of the BCG programmes quantitatively, in terms of hypothetical "gained and lost cases" in the various age-groups. They stress, however, that the significance of these gained and lost cases must be evaluated from an epidemiological viewpoint and that the relevant epidemiological factors must be taken into account in the planning of BCG programmes.