Search PubMed⌕ Search

Biomedical subjects

P K Andersen

Publications and source records attributed to P K Andersen.

At least 55 records · Page 3Linked to original sources
PubMed1999

A sensitivity analysis of secular trends in risk factors and mortality based on cohort studies.

Because of a "healthy responder effect," secular trends in mortality based on cohort studies may be biased if based on responders only. Because responders are selected on the basis of their health at study entry, subjects just entering a study are not comparable with subjects who have been in the study for several years. The result may be an artificial increase in mortality, which impedes analyzing the effect of secular trends in risk factors on mortality. The objective of this paper is to suggest a solution by using data on nonresponders and applying a sensitivity analysis. We illustrate this solution with data on trends in smoking prevalence and all-cause mortality based on a large Danish cohort study with 19 years of complete follow-up on responders and nonresponders. Secular trends in mortality based on the whole sample vs responders only illustrated that results based on responders were biased. In a sensitivity analysis, the observed person-years of nonresponders were distributed among six categories of persons with respect to smoking behavior (never-smokers; ex-smokers; noninhaling current smokers; and current smokers of 1-14, 15-24, and > or =25 gm tobacco per day) according to preset assumptions regarding smoking habits. The observed deaths among nonresponders were then distributed on the six smoking categories according to relative risks derived from a Poisson regression analysis among responders. This procedure allowed us to study the effect of adjustment for smoking on the unbiased secular trend in mortality. By applying different assumptions regarding smoking habits among nonresponders, we explored the effect of the assumptions on the adjusted secular trend in mortality. We conclude that secular trends in mortality based on responders in a cohort study are likely to be biased. If complete follow-up on nonresponders is available, this method could prove useful in other cohort studies.

Aged↗
PubMed1998

Declining HIV-2 prevalence and incidence among men in a community study from Guinea-Bissau.

OBJECTIVE: To assess the present level of HIV-2 infection in an adult population in Bissau and to evaluate sex and age-specific changes in HIV-2 prevalence and incidence between 1987 and 1996. DESIGN AND METHODS: Sex and age-specific changes in HIV-2 prevalence were evaluated comparing a survey from 1987 in a sample of 100 houses with a survey performed in 1996 in an independent sample of 212 houses from the same study area. HIV-2 incidence rates were examined in an adult population (age > or = 15 years) from 100 randomly selected houses followed with four consecutive HIV serosurveys from 1987 to 1996. RESULTS: The HIV-2 prevalence in 1996 was 6.8% (men, 4.7%; women, 8.4%). Compared with the 1987 survey there was a significant decrease in prevalence among men [age-adjusted relative risk (RR), 0.50; 95% confidence interval (CI), 0.31-0.83], whereas it remained unchanged in women (RR, 1.00; 95% CI, 0.67-1.48). The male-to-female RR decreased from 0.99 (95% CI, 0.61-1.61) in 1987 to 0.51 (95% CI, 0.34-0.76) in 1996. The overall annual incidence rate was 0.54 per 100 person-years of observation (PYO), being higher in women (0.72 per 100 PYO) than in men (0.31 per 100 PYO). With the observation time divided into an early and a late period, there was a decrease in incidence with time among men (0.66 to 0.00 per 100 PYO), but no major change among women (0.59 to 0.85 per 100 PYO). The two trends differed significantly (P = 0.03). We observed a higher annual incidence rate amongst older women aged > 44 years (1.77 per 100 PYO) than among younger women (0.55 per 100 PYO; P = 0.05). CONCLUSION: There are no signs of an epidemic spread of HIV-2 in Bissau even though the HIV-1 prevalence is increasing rapidly. A significant reduction in the male HIV-2 prevalence and incidence rates has resulted in a major shift in the pattern of spread of HIV-2, from being equally distributed to being predominantly a female infection. Currently, older women in particular seem to have a high risk of getting infected.

Adolescent↗
PubMed1998

[Induced abortion and risk of breast cancer].

It has been hypothesized that an interrupted pregnancy might increase the risk of breast cancer, because proliferation of breast cells will take place without the protective effect of subsequent differentiation. In a cohort of 1.5 million women (28.5 million person-years) we identified 370,715 induced abortions in 280,965 women (2.7 million person-years) and 10,246 women with breast cancer. After adjustment for other risk factors, induced abortion was not associated with the risk of breast cancer (relative risk: 1.00; 95 percent confidence interval 0.94 to 1.06). However, the relative risk of breast cancer increased with increasing gestational age of the most recently induced abortion: < 7 weeks: 0.81; 7 to 8 weeks; 1.01; 9 to 10 weeks: 1 (reference); 11 to 12 weeks: 1.12; 13 to 14 weeks: 1.13; 15 to 18 weeks: 1.23; > 18 weeks: 1.89; P(trend) = 0.016. On a population basis, induced abortion was not associated with an increased risk of breast cancer. An increase was only seen for the special group of late second trimester abortions, but this finding was based on small numbers.

Abortion, Induced↗
PubMed1998

Differences in susceptibility to AIDS development: a cohort study of Danish and American homosexual-bisexual men, 1981 to 1995.

We estimated the annual hazard rate for progression to AIDS as defined by the 1987 case definition in HIV-infected members of a cohort of Danish and American homosexual-bisexual men who were observed from 1981 to 1995. Furthermore, we extrapolated the hazard to 25 years based on imputed future time to AIDS. Of 201 HIV-positive subjects, 112 developed AIDS before the end of follow-up. The hazard increased rapidly during the first years following infection, attained a peak of about 15% per year at year 7, and was moderately lower during years 8 through 10. In subsequent analysis, we imputed future time to AIDS in 89 subjects who had not progressed by the end of follow-up by extrapolation from subject-specific CD4 trend lines. A CD4 count of < or = 100 cells/microl was the best surrogate for clinical AIDS. Under this model, the imputed AIDS hazard stabilized at around 8% per year after 10 years. We projected that 13% (95% confidence interval [CI], 8%-19%) of the infected men may remain free from AIDS 25 years after seroconversion. Our direct data suggest that incubation times reflect a mixture of a population that is susceptible to disease progression and has short incubation periods with a group that is relatively resistant. Based on an extrapolation model, > 10% of HIV-infected persons may survive for up to 25 years without developing AIDS.

Acquired Immunodeficiency Syndrome↗
PubMed1998

Predictors of recurrence in affective disorder. A case register study.

BACKGROUND: The risk of recurrence in affective disorder is affected by socio-demographic variables such as gender, age at onset and marital status and by illness related factors as the length of previous episodes and the total duration of the illness. The present study investigated how the effect of these variables changed with the progression of the illness. METHOD: Using survival analysis, the risk of recurrence was estimated in a case register study including all hospital admissions with primary affective disorder in Denmark during 1971-1993. RESULTS: Totally, 20350 first admission patients had been discharged with a diagnosis of affective disorder, depressive or manic/circular type. Initially in the course of the illness, bipolar patients had a substantial greater risk of recurrence compared with unipolar patients. At this time, gender, age and marital status together with the total duration of the illness predicted the risk of recurrence in both unipolar and bipolar illness. Some variables had different predictive effect in the two types of illness. Later, especially the duration of the previous illness predicted the risk of recurrence. CONCLUSION: It seems as initially in the course of affective disorder socio-demographic variables such as gender, age at onset and marital status act as risk factors for further recurrence. Later, however, the illness itself seem to follow its own rhythm regardless of prior predictors. LIMITATION: The data relate to re-admissions rather than recurrence and the findings may be due to decreasing sample sizes during the course of illness. CLINICAL RELEVANCE: The study underscores the importance of the illness process itself.

Adult↗
PubMed1998

Testicular cancer risk and maternal parity: a population-based cohort study.

The aim was to study, in a population-based cohort design, whether first-born sons run a higher risk of testicular cancer than later born sons; to investigate whether this difference in risk was affected by birth cohort, age of the son, maternal age, interval to previous delivery and other reproductive factors; and, finally, to evaluate to what extent changes in women's parity over time might explain the increasing incidence of testicular cancer. By using data from the Civil Registration System, a database was established of all women born in Denmark since 1935 and all their children alive in 1968 or born later. Sons with testicular cancer were identified in the Danish Cancer Registry. Among 1015994 sons followed for 15981 967 person-years, 626 developed testicular cancer (443 non-seminomas, 183 seminomas). Later born sons had a decreased risk of testicular cancer (RR = 0.80, 95% CI = 0.67-0.95) compared with first-born sons. The RR was 0.79 (95% CI = 0.64-0.98) for non-seminomas and 0.81 (95% CI = 0.58-1.13) for seminomas. There was no association between testicular cancer risk and overall parity of the mother, maternal or paternal age at the birth of the son, or maternal age at first birth. The decreased risk of testicular cancer among later born sons was not modified by age, birth cohort, interval to the previous birth, sex of the first-born child, or maternal age at birth of the son or at first birth. The increased proportion of first-borns from birth cohort 1946 to birth cohort 1969 only explained around 3% of an approximated two-fold increase in incidence between the cohorts. Our data document a distinctly higher risk of testicular cancer in first-born compared with later born sons and suggest that the most likely explanation should be sought among exposures in utero. The increase in the proportion of first-borns in the population has only contributed marginally to the increase in testicular cancer incidence.

Adolescent↗
PubMed1998

Effectiveness of a dietary intervention strategy in general practice: effects on blood lipids, health and well-being.

OBJECTIVES: To evaluate the effect of a dietary treatment programme on blood cholesterol concentration in hypercholesterolaemic patients in general practice and to analyse subjectively experienced side-effects. DESIGN: A 1-year parallel trial comparing a new treatment programme with conventional treatment. SETTING: General practitioners in Roskilde county, Denmark. SUBJECTS: 355 men and women, aged 20-60 years, with a persistent blood cholesterol concentration above age- and gender-specific cut-off points (265 in an intervention group and 90 in a control group). INTERVENTION: A treatment strategy based on collaboration between doctor and dietitian using individual dietary advice and feedback from measured biological parameters. MAIN OUTCOME MEASURES: Serum lipids, body weight, blood pressure, dietary behaviour, health parameters, quality of life parameters and acceptance by patients and general practitioners. RESULTS: Total blood cholesterol concentration decreased by 14% (1.07 mmol l(-1), P < 0.0001) in 159 patients in the intervention group, not having any lipid altering drug during treatment, in addition to 3% from screening to start of treatment. In 65 patients in the control group, without any lipid altering drug, the reduction of cholesterol concentration was 4% (0.27 mmol l(-1), P < 0.01; intervention vs. control P < 0.001). In the intervention group overweight subjects (body mass index > 30) reduced body weight by 6% (P < 0.0001). Systolic blood pressure was reduced by 11% (P < 0.0001) and diastolic blood pressure by 10% (P < 0.0001) and 19% (P < 0.003) for intervals 90-110 mmHg and > 110 mmHg, respectively. Risk score decreased and self-assessed health, physical and psychological well-being improved. CONCLUSIONS: The treatment strategy tested proved to be efficient, without side-effects and well accepted by patients and general practitioners. The results strongly suggest that hypercholesterolaemia can efficiently be treated non-pharmacologically in general practice.

Adult↗
PubMed1998

Mortality in women and men in relation to smoking.

BACKGROUND: Mortality from smoking-related diseases in women is increasing worldwide. Studies comparing hazards associated with smoking in women and men based on a sufficient number of heavy smokers of both genders are lacking. METHODS: We used pooled data from three prospective population studies conducted in Copenhagen to compare total and cause-specific mortality in relation to smoking habits. A total of 30917 subjects, 44% women, with initial examinations between 1964 and 1992 were followed until 1994 for date and cause of death. RESULTS: During follow up, 2900 women and 5744 men died. Smoking characteristics differed considerably with gender, particularly in the older subjects. Overall mortality rates in smokers were approximately twice those in people who never smoked. Positive associations with smoking in both men and women were confirmed for all-cause mortality as well as mortality from respiratory disease, vascular disease, lung cancer, and other tobacco-related cancers. Despite large gender differences in age at smoking debut, total and cause-specific relative mortality in smokers was similar in men and women. After excluding non-inhalers, relative risks associated with smoking for respiratory and vascular disease were higher for women than men whereas there were no gender differences in smoking related risk of cancers. CONCLUSIONS: The relative risks suggest that women may be more sensitive than men to some of the deleterious effects of smoking. However, because of lower baseline mortality rates in women, rate differences may be similar and results should be interpreted with caution.

Adolescent↗
PubMed1998

Recurrence in affective disorder. I. Case register study.

BACKGROUND: In recent years, studies of the risk of recurrence in affective disorder in relation to the number of prior episodes have given contradictory results. METHOD: Survival analysis was used to calculate the rate of recurrence after successive episodes in a case register study including all hospital admissions with primary affective disorder in Denmark during 1971-1993. A total of 20,350 first-admission patients were discharged with a diagnosis of affective disorder, depressive or manic/cyclic type. RESULTS: The rate of recurrence increased with the number of previous episodes in both unipolar and bipolar disorder. Initially, the two types of disorders followed markedly different courses, but later in the course of the illness the rate of recurrence was the same for the two disorders. CONCLUSIONS: The course of severe unipolar and bipolar disorder seems to be progressive in nature despite the effect of treatment.

Adult↗
PubMed1997

Birth order, sibship size and risk of Hodgkin's disease in children and young adults: a population-based study of 31 million person-years.

It has been proposed that Hodgkin's disease (HD) may have an infectious origin and that delayed exposure to infection may increase the risk of HD in young adults. This hypothesis is addressed by studying the family structure among children and young adults. The Civil Registration System was used to establish a population-based cohort consisting of all persons whose mothers were born in Denmark since 1935. Persons who developed HD were identified by linkage with the Danish Cancer Registry. HD incidence rate ratios were estimated based on a log-linear Poisson regression model. The cohort of 2.1 million persons (aged 0-42 years) was followed for 31.1 million person years, during which period 378 cases of HD occurred. Among children (< 15 years, n = 72), the relative risk (RR) of HD tended to increase with increasing sibship size, the relative increase in risk per increase in sibship size (the trend) being 1.28 [95% confidence interval (CI) 1.00-1.63]. The trend for birth order was 1.26 (95% CI 0.92-1.73). Among young adults (> or = 15 years, n = 306) the risk of HD, on the contrary, tended to decrease with increasing sibship size [trend = 0.91 (95% CI, 0.81-1.03)] and birth order (trend = 0.85 (95% CI, 0.71-1.01). These trends among young adults were significantly different from the corresponding trends among children (p < 0.05). Siblings of cases were at increased risk of HD (RR = 18; 95% CI, 2.2-65, n = 2). Our findings are compatible with the hypothesis that delayed exposure to infection may be a risk factor for HD in young adults, and that early exposure perhaps to another infectious agent may increase the risk of HD in children.

Adolescent↗
PubMed1997

Birth characteristics, sibling patterns, and acute leukemia risk in childhood: a population-based cohort study.

BACKGROUND: The occurrence of acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML) during childhood may be influenced by factors operating in fetal life. Furthermore, childhood ALL has been suggested to be linked to patterns of infection during infancy. PURPOSE: To explore these hypotheses and other associations, we studied the impact of sibling patterns (e.g., birth order) and birth characteristics (e.g., birth weight) on the risk of childhood ALL and AML. METHODS: By linkage of records of population-based registries, a cohort of all children whose mothers were born in Denmark from April 1935 through March 1978 was established. Children who developed ALL or AML during the period from April 1968 through December 1992 were identified by linkage with the Danish Cancer Registry. Birth weights were obtained for children born during the period from January 1973 through December 1992 by linkage with the Medical Birth Registry. RESULTS: The cohort of approximately 2.0 million children was followed for the diagnosis of ALL or AML for 20.9 million person-years. A total of 704 cases of childhood ALL were identified. Among 0-4 year olds, the relative risks (RRs) of ALL for birth order positions 1, 2, 3, and 4+ were 1.00 (reference), 0.85 (95% confidence interval [CI] = 0.68-1.07), 0.91 (95% CI = 0.66-1.25), and 0.57 (95% CI = 0.30-1.06), respectively (P for trend = .09). A decreasing trend was not observed among 5-14 year olds. A significant log-linear association between birth weight and the risk of ALL was observed for both age groups. Overall, the RR of ALL increased by a factor of 1.46 (95% CI = 1.18-1.81) (P = .0005) for each kilogram of increase in birth weight. A total of 114 cases of childhood AML were identified. Children born second or later in the birth order had an increased risk of AML (RR = 1.53; 95% CI = 1.01-2.32) compared with firstborns. A particularly high risk of AML at ages 2 (RR = 2.53; 95% CI = 1.46-4.40) and 3 years was associated with having siblings compared with being an only child at those ages. Similar to the findings for ALL risk, there was a significant association between birth weight and AML risk. The relative increase in AML risk per 1-kg increase in birth weight was 2.14 (95% CI = 1.19-3.85; P = .009). CONCLUSION AND IMPLICATIONS: The association between birth weight and childhood leukemia suggests the importance of intrauterine factors. A plausible explanation may be that increasing birth weight is associated with a higher rate of cell proliferation and/or a larger number of precursor cells being at risk of malignant transformation. The inverse association between birth order and ALL risk among 0-4 year olds was weak, but it was compatible with the hypothesis that delayed exposure to infection may increase the risk of ALL in this age group. The association of childhood AML with birth order and sibship size at young ages deserves further attention in the search for environmental factors that affect childhood AML risk.

Acute Disease↗
PubMed1997

Progression to acquired immunodeficiency syndrome is influenced by CD4 T-lymphocyte count and time since seroconversion.

Progression to acquired immunodeficiency syndrome (AIDS) among persons infected with human immunodeficiency virus (HIV) varies considerably and may be influenced by factors such as age, smoking, number of male partners per year, and CD4 T-lymphocyte count. The loss of CD4 lymphocytes is known to be the dominant factor in the progression to AIDS. However, it is unclear whether the effect of the CD4 lymphocyte count is of such importance that persons with similar CD4 cell counts who have been infected for widely different lengths of time have the same risk of AIDS. While a CD4 count is easily obtainable, the precise amount of time since HIV infection is in most circumstances difficult to assess. In the present analysis, 259 Danish and 245 American homosexual men were followed for up to 14 years from 1981 to 1995. Two hundred and one persons seroconverted during the study period, and 112 had developed AIDS before the end of follow-up. CD4 lymphocyte count was highly correlated with the risk of developing AIDS (p < 0.001), but AIDS risk was not affected significantly by either age at infection, smoking, or number of male partners per year (p > 0.20 in all cases). Controlled for CD4 lymphocyte count, time since seroconversion was significant in explaining the risk of AIDS (p = 0.018), with a lower risk being seen during the first 3 years after seroconversion but no effect thereafter. These data confirm the central importance of CD4 lymphocyte level in the progression of HIV disease to AIDS, and suggest that rapid progression within 3 years of infection may be related to factors other than CD4 cell count.

Acquired Immunodeficiency Syndrome↗
PubMed1997

Induced abortion and the risk of breast cancer.

BACKGROUND: It has been hypothesized that an interrupted pregnancy might increase a woman's risk of breast cancer because breast cells could proliferate without the later protective effect of differentiation. METHODS: We established a population-based cohort with information on parity and vital status consisting of all Danish women born from April 1, 1935, through March 31, 1978. Through linkage with the National Registry of Induced Abortions, information on the number and dates of induced abortions among those women was combined with information on the gestational age of each aborted fetus. All new cases of breast cancer were identified through linkage with the Danish Cancer Registry. RESULTS: In the cohort of 1.5 million women (28.5 million person-years), we identified 370,715 induced abortions among 280,965 women (2.7 million person-years) and 10,246 women with breast cancer. After adjustment for known risk factors, induced abortion was not associated with an increased risk of breast cancer (relative risk, 1.00; 95 percent confidence interval, 0.94 to 1.06). No increases in risk were found in subgroups defined according to age at abortion, parity, time since abortion, or age at diagnosis of breast cancer. The relative risk of breast cancer increased with increasing gestational age of the fetus at the time of the most recent induced abortion: <7 weeks, 0.81 (95 percent confidence interval, 0.58 to 1.13); 7 to 8 weeks, 1.01 (0.89 to 1.14); 9 to 10 weeks, 1.00 >12 weeks, 1.38 (1.00 to 1.90) (reference category, 9 to 10 weeks). CONCLUSIONS: Induced abortions have no overall effect on the risk of breast cancer.

Abortion, Induced↗
PubMed1997

Has risk associated with smoking increased? Results from the Copenhagen Center for Prospective Population Studies.

BACKGROUND: Two recent much cited publications have raised the concern that risk associated with cigarette smoking has so far been underestimated. In this study we wish to determine whether excess all-cause mortality associated with smoking has increased during the last 20-30 years in a study population representative of the general Danish population and whether any such changes relate to changes in smoking behaviour. METHODS: Pooled data from three prospective population studies conducted in Copenhagen with detailed information on smoking habits. A total of 31,194 subjects, 17,669 males and 13,525 females, initially examined between 1964 and 1992 with examinations repeated at intervals from 1-10 years, were followed until 1995 for all-cause mortality. Relative mortality risk in smokers versus never-smokers was calculated within periods of five calendar years and compared throughout the study period. RESULTS: Male smokers' exposure did not change during the study period whereas female smokers' exposure to tobacco increased in terms of age at smoking onset, quantity smoked and depth of inhalation. During follow-up 5744 males and 2900 females died. In males, death rate ratios (comparing continuous smokers with never-smokers) did not change in the study period. In females, ratios increased from 1964-1978 to 1979-1994 by a factor of 1.3 (95% confidence interval 1.0-1.8). CONCLUSIONS: In agreement with the observed changes in smoking habits, excess mortality in male smokers did not increase whereas excess mortality in female smokers increased slightly.

Adolescent↗
PubMed1997

Does in-hospital ventricular fibrillation affect prognosis after myocardial infarction?

AIM: The aim of this study was to estimate the prognostic information to be gained from ventricular fibrillation in patients with myocardial infarction. METHODS AND RESULTS: We studied 4259 consecutive patients with myocardial infarction admitted to one centre in 1977-1988. Five hundred and twenty-eight (12.4%) of the patients had ventricular fibrillation in hospital. The following risk factors were included in multivariate models to estimate their importance for 30-day and long-term (median 7 year) prognosis: age, gender, ventricular fibrillation, congestive heart failure, pulmonary oedema, cardiogenic shock, other cardiac arrest and atrial fibrillation. We found that the odds ratio for death on days 6.30 was 6.34 (3.55-11.30, 95% confidence limits, P < 0.001) for patients with primary ventricular fibrillation (without heart failure) and 4.06 (2.68-6.14, P < 0.001) for patients with ventricular fibrillation secondary to heart failure compared to patients without ventricular fibrillation. For patients surviving more than 30 days, relative risk of death in those with ventricular fibrillation was 1.11 (95% confidence interval 0.93-1.34, P = 0.26). Logistic regression analysis of relative risk associated with ventricular fibrillation in time intervals, indicated that the importance of ventricular fibrillation for risk of death was exhausted during the initial 60 days after infarction. CONCLUSION: Ventricular fibrillation is associated with an independent increased risk of death within 0-60 days after infarction. After this period, the prognosis in survivors of ventricular fibrillation does not differ significantly from patients without ventricular fibrillation.

Adult↗
PubMed1997

Cardiovascular risk factor profile in subjects with familial predisposition to myocardial infarction in Denmark.

STUDY OBJECTIVES: To identify possible modifiable mediators of familial predisposition to myocardial infarction (MI) by assessing the risk factor profile in individuals without MI in relation to parental occurrence of MI. DESIGN AND METHODS: Cross sectional survey of the general population. The odds of an adverse cardiovascular risk factor profile in subjects reporting parental occurrence of MI versus subjects not reporting parental occurrence were estimated by logistic regression models. SETTING: The Copenhagen Centre for Prospective Population Studies, where subjects investigated in three Danish prospective population studies are integrated. PARTICIPANTS: Subjects were 9306 females and 11,091 males aged 20-75 years with no history of MI. A total of 1370 subjects reported maternal MI and 2583 reported paternal MI. MAIN RESULTS: Increased systolic and diastolic blood pressure, increased cholesterol level, low ratio between high density lipoprotein (HDL) and total cholesterol (TC), and heavy smoking, were more frequent in subjects with parental occurrence of MI than in controls irrespective of sex and age of the subjects. Maternal MI was more predictive for increased cholesterol and decreased HDL/ TC ratio than paternal MI, and the risk of an increased cholesterol level was higher in subjects aged 20-39 years than in older subjects. No differences in body mass index, triglycerides, and physical inactivity were observed. CONCLUSIONS: Subjects free of previous MI who reported a parental occurrence of MI had an adverse cardiovascular risk factor profile regarding systolic and diastolic blood pressure, total cholesterol, the ratio between HDL and total cholesterol, and smoking. Thus, these modifiable risk factors may be mediators of the familial predisposition to MI.

Adult↗
PubMed1997

Gender difference in smoking effects on lung function and risk of hospitalization for COPD: results from a Danish longitudinal population study.

Recent findings suggest that females may be more susceptible than males to the deleterious influence of tobacco smoking in developing chronic obstructive pulmonary disease (COPD). This paper studies the interaction of gender and smoking on development of COPD as assessed by lung function and hospital admission. A total of 13,897 subjects, born after 1920, from two population studies, 9,083 from the Copenhagen City Heart Study (CCHS) and 4,814 from the Glostrup Population Studies (GPS), were followed for 7-16 yrs. Data were linked with information on hospital admissions caused by COPD. Based on cross-sectional data, in the CCHS the estimated excess loss of forced expiratory volume in one second (FEV1) per pack-year of smoking was 7.4 mL in female smokers who inhaled and 6.3 mL in male smokers who inhaled. In the GPS, the corresponding excess loss of FEV1 was 10.5 and 8.4 mL in females and males, respectively. Two hundred and eighteen subjects in the CCHS and 23 in the GPS were hospitalized during follow-up. Risk associated with pack-years was higher in females than in males (relative risks (RRs) for 1-20, 20-40 and >40 pack-years were 7.0 (3.5-14.1), 9.8 (4.9-19.6) and 23.3 (10.7-50.9) in females, and 3.2 (1.1-9.1), 5.7 (2.2-14.3) and 8.4 (3.3-21.6) in males) but the interaction term gender x pack-years did not reach significance (p=0.08). Results were similar in the GPS. After adjusting for smoking in more detail, females in both cohorts had an increased risk of hospitalization for COPD compared to males with a RR of 1.5 (1.2-2.1) in the CCHS and 3.6 (1.4-9.0) in the GPS. This was not likely to be caused by a generally increased rate of hospital admission for females. Results were similar when including deaths from COPD as endpoint. In two independent population samples, smoking had greater impact on the lung function of females than males, and after adjusting for smoking females subsequently suffered a higher risk of being admitted to hospital for COPD. Results suggest that adverse effects of smoking on lung function may be greater in females than in males.

Adult↗