Search PubMed⌕ Search

Biomedical subjects

A Ekbom

Publications and source records attributed to A Ekbom.

At least 199 records · Page 11Linked to original sources
PubMed1995

Parity and risk of thyroid cancer: a nested case-control study of a nationwide Swedish cohort.

The association between parity and risk of thyroid cancer was examined in a case-control study nested within a cohort of Swedish women born 1925-60. A total of 1,409 cases of thyroid cancer were compared with 7,019 age-matched controls. Odds ratios (OR) and 95 percent confidence intervals (CI) were calculated as estimates of relative risk. A weak association was found between parity and risk of thyroid cancer (OR for ever-parous women cf nulliparous was 1.1, CI = 1.0-1.3). For the subset of papillary cancers, there was a significantly increased risk (OR for ever-parous cf nulliparous = 1.3, CI = 1.0-1.6), and among women diagnosed at the age of 50 or older, there was a positive linear trend with increasing number of livebirths. Women during the first year after a livebirth had an increased risk of thyroid cancer compared with women who delivered 10 or more years before; this association was most prominent among uniparous women (OR = 2.5, CI = 1.1-5.9). An increased risk was also apparent for age over 20 years at livebirth (among uniparous women) and age over 25 years at last livebirth (among multiparous women). A negligible effect of parity on thyroid cancer risk was seen, but each livebirth may have a short-term and age-dependent promoting effect.

Adenocarcinoma, Follicular↗
PubMed1995

Crohn's disease: pathogenesis and persistent measles virus infection.

The Inflammatory Bowel Disease Study Group at the Royal Free Hospital School of Medicine has tested the hypothesis that the primary pathological abnormality in Crohn's disease is in the mesenteric blood supply. Early morphological studies involved arterial perfusion-fixation and either resin casting and scanning electron microscopy or vascular immunostaining of resected intestine affected by Crohn's disease. Granulomatous and lymphocytic damage to intramural blood vessels, even in macroscopically normal areas, was observed. We put forward possible mechanisms by which a chronic ischemic process might account for many of the idiosyncracies of Crohn's disease. It was proposed that persistent viral infection of the mesenteric microvascular endothelium might underly this vasculitic process; based on certain behavioral characteristics of measles virus, including its tropism for the submucosal endothelium of the intestine, this agent was investigated further. This report reviews the preliminary evidence from both epidemiological and basic scientific data for persistent measles virus in the intestine of patients with Crohn's disease. Possible mechanisms for virus persistence and subsequent reactivation are discussed. In conclusion, we believe that Crohn's disease may be a chronic granulomatous vasculitis in reaction to a persistent infection with measles virus within the vascular endothelium. This granulomatous inflammation, perhaps aggravated by either a hypercoagulable state or mechanical stress, results in the clinical features of Crohn's disease.

Colon↗
PubMed1995

The aetiology and pathogenesis of human breast cancer.

Whilst investigators have clearly shown that non-hereditary factors dominate the aetiology of human breast cancer, they have failed to identify quantitatively important causes, and prospects for prevention remain indeed limited. However, progress in epidemiological and basic research has taken place during the last few years. Current evidence suggests that breast cancer may be affected by the intra-uterine environment, that exposures during adolescence are particularly important, and that pregnancy has a dual effect on breast cancer risk: an early increase followed by long-term protection. Great variation exists in the structural development of the breast ductal system already in the newborn--and by inference in utero--and a pregnancy induces permanent structural changes in the mammary gland. We suggest that these observations fit into an aetiological model with the following key components: (1) breast cancer risk depends on the number of cells at risk, the susceptibility of individual cells to malignant transformation, and on the degree of cellular proliferation, notably cells which can act as founders of breast cancer; (2) the number of target cells is determined by the hormonal environment mainly early in life, perhaps already in utero; (3) in adult life, hormones which are non-genotoxic, increase breast cancer risk by increasing selective cell proliferation and thus number of target cells and the risk of retention of spontaneous somatic mutations; (4) while a pregnancy stimulates the growth of already malignant cells or cells close to malignant transformation (and thereby entails a short-term risk increase) the dominating long-term protection occurs due to permanent structural changes, terminal differentiation and perhaps decreased cell proliferation and carcinogen-binding in combination.

Adult↗
PubMed1995

High birthweight as a predictor of prostate cancer risk.

In a follow-up study of a cohort of 50-year-old men who were born in 1913 and were living in Gothenburg, Sweden, we found an association between birthweight and prostate cancer. Of 366 men with known birthweight, there were 21 patients with prostate cancer. The incidence is about five times higher in the highest quartile of birthweight than in other birthweight groups. The findings indicate that aspects of the pre- and perinatal period may affect the risk of subsequent prostate cancer.

Birth Weight↗
PubMed1995

Parental age and breast cancer mortality.

Because older ages of both mothers and fathers have been hypothesized by others to increase the subsequent risk of breast cancer in female babies, we analyzed the association between maternal and paternal age at birth and mortality from breast cancer in a cohort of 384,796 American women. Cox proportional hazards modeling accounted for age, family history of breast cancer in first-degree relatives, age at menarche, age at first pregnancy, and parity. We found little association between paternal age at birth and death from breast cancer. Although there was no clear linear trend for higher risk with increasing age of the mothers at birth, women born to mothers age 45 years or older had a relative hazard of 1.30 (95% confidence interval = 0.85-1.98), compared with women born to mothers under the age of 20 years. Although these findings are of little public health significance, they may indicate a hormonal profile in older mothers that predisposes female offspring to a higher risk of breast cancer in later years.

Adult↗
PubMed1995

Incidence of inflammatory bowel disease in southeastern Norway: evaluation of methods after 1 year of registration. Southeastern Norway IBD Study Group of Gastroenterologists.

To assess the feasibility of a prospective incidence study of inflammatory bowel disease (IBD), the registration methods and incidence figures during 1990 were evaluated. The study was a collaboration between 14 hospitals in an area of close to one million inhabitants. Common diagnostic criteria for ulcerative colitis (UC), Crohn's disease (CD) and indeterminate colitis (IND) were established prior to the start of the study. There was an overall incidence rate for IBD of 19.3 per 10(5) inhabitants, with 10.6 for UC, 5.1 for CD and 3.6 for IND. The age-specific incidence rates showed a peak between 25 and 34 years for UC and between 15 and 25 for CD. There was a male predominance for UC and a female preponderance for CD. These results are comparable with the previous registrations in western and northern areas of Norway.

Adolescent↗
PubMed1995

Cancers among patients diagnosed as having diverticular disease of the colon.

OBJECTIVE: To assess the incidence of underlying malignancy in patients with a diagnosis of diverticular disease of the colon. DESIGN: Retrospective cohort study. SETTING: University hospital, Sweden. SUBJECTS: 7159 patients discharged from hospital with a first diagnosis of diverticulosis or diverticulitis in central Sweden 1965-1983. INTERVENTION: The cohort was followed up for two years for the occurrence of cancer. MAIN OUTCOME MEASURE: Cancer incidence. RESULTS: A total of 372 cancer cases were identified standard incidence ratio = 2.4; 95% confidence interval 2.2 to 2.7). Sites at excess risk during the first year were: colon and rectum, pancreas, prostate, stomach, lymphatic and haemopoietic tissue, liver and bile ducts, ovary and lung, with the highest excess risk in the left colon (standard incidence ratio = 17.8; 95% CI 12.7 to 24.1). CONCLUSION: Malignant diseases, especially colorectal cancer, are relatively common among patients with a clinical diagnosis of diverticulosis or diverticulitis of the colon. This may indicate a need for a change in current clinical practice.

Aged↗
PubMed1994

Parity, age at first childbirth, and risk of ovarian cancer.

Increasing parity is associated with a reduction in the risk of ovarian cancer, but it is not clear whether this association applies to different histopathological types and to borderline tumours. Moreover, the temporal relations are poorly understood, and the possible role of age at first birth remains unequivocal. We have investigated these issues in a case-control study nested in a nationwide cohort of women born between 1925 and 1960 in Sweden. During follow-up until 1984, 3486 invasive ovarian cancers (2992 epithelial, 330 stromal, 149 germ-cell, 15 not classifiable) and 510 tumours of borderline malignant potential were diagnosed. 5 individually age-matched controls (total 19,980) were selected for each case woman. After simultaneous adjustment for parity and age at first birth, increasing parity was associated with a pronounced consistent decrease in relative risk of all invasive cancers (odds ratio for each additional birth 0.81 [95% Cl 0.77-0.85]), epithelial cancer (0.81 [0.77-0.86]), stromal cancer (0.84 [0.72-0.98]), and germ-cell cancer (0.71 [0.48-1.05]), but a less consistent decrease for borderline tumours (0.92 [0.81-1.04]). The risk of ovarian cancer decreased by about 10% for each 5-year increment in age at first childbirth (odds ratios 0.89 [0.84-0.94] epithelial cancer, 0.92 [0.77-1.10] stromal cancer, 0.92 [0.65-1.32] germ-cell cancer, 0.93 [0.80-1.09] borderline tumours). Because our findings cannot be readily explained by theories involving incessant ovulation or high serum concentrations of gonadotropins, new aetiological hypotheses are needed. Pregnancy-dependent clearance from the ovaries of cells that have undergone malignant transformation could explain the reproductive risk factors for ovarian cancer.

Adolescent↗
PubMed1994

Testicular cancer in nine northern European countries.

The incidence of testicular cancer was examined in the Nordic and Baltic countries, Poland and Germany by collaboration among 10 cancer registries. Population-based registers were used to analyze a total of 34,309 cases, diagnosed from the start of registration (varying from 1943 in Denmark to 1980 in Latvia and Lithuania) through 1989. An approximately 10-fold geographical variation was found in 1980, with the highest age-standardized incidence rate (7.8 per 10(5); world standard population) in Denmark and the lowest (0.9) in Lithuania. During the entire period of registration, incidence increased rapidly in all countries, by 2.3 to 3.4 per cent annually in the Nordic countries and by about 5 per cent in Poland and Germany; there was some evidence of a slower increase in Denmark and Poland after 1975. The rising trend was more pronounced for ages below 30. The age-specific incidence peaked in all countries at ages 25 to 34, but the geographical variation was considerable. Our data indicate that environmental influences on testicular cancer are strong. Exposure to causal factors mostly takes place early in life, shows substantial geographical variation, and increases over time, so that the age-standardized incidence doubles every 15 to 25 years. New aetiological hypotheses are needed to accommodate these salient features of the descriptive epidemiology, since risk factors considered so far cannot explain the observed pattern.

Adolescent↗
PubMed1994

Perinatal measles infection and subsequent Crohn's disease.

Although the aetiology of Crohn's disease is unknown, morphological and epidemiological studies have implicated measles virus as a potential component cause, particularly when exposure occurs in utero or early in life. An increased incidence of Crohn's disease among people born during measles epidemics would support this hypothesis. We identified all individuals born in four counties in central Sweden in 1945-54 who had had Crohn's disease diagnosed before the age of 30 years. Yearly reports compiled in these counties revealed that five measles epidemics had affected all four counties during the trial period. After adjusting for monthly differences in the number of livebirths in the four counties, we calculated the expected number of patients with Crohn's disease and ulcerative colitis born during the 3-month period after the peaks of the epidemics. The number of people with Crohn's disease significantly exceeded that expected: 57 versus 39.0 (standardised incidence ratio 1.46, 95% CI 1.11-1.89). For patients with ulcerative colitis, the observed number (42) was close to that expected (46.8). Our results strengthen the hypothesis that measles is related to Crohn's disease and that the perinatal period is a time of vulnerability.

Adult↗
PubMed1994

Transient increase in the risk of breast cancer after giving birth.

BACKGROUND: The effect of pregnancy on the risk of breast cancer is not clear. We tested the hypothesis that the risk of breast cancer increases transiently after pregnancy but then falls to a level below that of age-matched nulliparous women. METHODS: We conducted a case-control study of a nationwide cohort in Sweden, using a computerized record linkage between the Cancer Registry and the Fertility Registry. The study subjects were women born from 1925 through 1960 who were resident citizens of Sweden at the time of the 1960 census. A total of 12,666 patients with breast cancer were compared with 62,121 age-matched control subjects. We used conditional logistic regression to estimate odds ratios for the development of breast cancer at different ages, according to maternal age at first delivery (in uniparous as compared with nulliparous women) and age at second delivery (in biparous as compared with uniparous women). RESULTS: Uniparous women were at higher risk of breast cancer than nulliparous women for up to 15 years after childbirth and at lower risk thereafter. The excess risk was most pronounced among women who were older at the time of their first delivery (odds ratio 5 years after delivery among women 35 years old at first delivery, 1.26; 95 percent confidence interval, 1.10 to 1.44). Women who had two pregnancies had a less striking increase in risk. CONCLUSIONS: Pregnancy has a dual effect on the risk of breast cancer: it transiently increases the risk after childbirth but reduces the risk in later years. In women with two pregnancies, the short-term adverse effect is masked by the long-term protection imparted by the first pregnancy. A plausible biologic interpretation is that pregnancy increases the short-term risk of breast cancer by stimulating the growth of cells that have undergone the early stages of malignant transformation but that it confers long-term protection by inducing the differentiation of normal mammary stem cells that have the potential for neoplastic change.

Adult↗
PubMed1994

Pancreatitis and pancreatic cancer: a population-based study.

BACKGROUND: Little is known about the etiology of cancer of the exocrine portion of the pancreas, which produces a variety of digestive enzymes. Smoking, certain dietary factors, and diabetes mellitus are considered to be risk factors, although the risk estimates are modest in most instances. A recent cohort study of patients with chronic pancreatitis indicated a ninefold to 16-fold increased risk for pancreatic cancer. PURPOSE: Our purpose was to evaluate the relationship between various clinical types of pancreatitis and pancreatic cancer. METHODS: Data for this study were collected from all inpatient medical institutions in Sweden from 1965 until 1983 by the Swedish National Board of Health and Welfare. Data were recorded on individual hospital admissions and discharges in the Inpatient Register. All patients with records in the Inpatient Register coded for acute, chronic, or unspecified pancreatitis were considered for inclusion in the study. A population-based cohort of 7956 patients with at least one discharge diagnosis of pancreatitis was monitored (up to 19 years of follow-up) for the occurrence of pancreatic cancer by record linkages to the Swedish Cancer Registry and Registry of Causes of Death. RESULTS: A total of 46 pancreatic cancers were diagnosed during follow-up compared with 21 expected (standardized incidence ratio [SIR] of 2.2; 95% confidence interval [CI] 1.6-2.9) for the Uppsala Health Care Region. The excess risk for women and men was similar--most pronounced during the first period of follow-up (2-4 years) after discharge and close to unity after more than 10 years of follow-up. Patients with chronic pancreatitis and patients with more than one discharge diagnosis of either acute or unspecified pancreatitis were at higher risk (SIR = 3.8; 95% CI 1.4-8.2 and SIR = 4.8; 95% CI 1.9-9.9, respectively) compared with those with only one discharge of acute (SIR = 1.6; 95% CI 0.9-2.7) or unspecified (SIR = 2.1; 95% CI 1.2-3.2) pancreatitis. CONCLUSIONS: Our finding of a moderate excess of pancreatic cancer among patients with pancreatitis, especially the chronic or recurrent forms, supports some earlier clinical and case-control studies, but it is not consistent with the ninefold to 16-fold risk reported in a recent cohort study. The absence of an increased risk 10 years or more after first discharge for pancreatitis argues against a straight-forward causal relationship. Because of the relatively short interval between diagnosis of pancreatitis and pancreatic cancer, it is possible that some forms of pancreatitis are a precursor to pancreatic cancer or that shared risk factors for both diseases (e.g., cigarette smoking) may also be involved.

Acute Disease↗
PubMed1994

Epidemiologic correlates of breast cancer laterality (Sweden).

Breast cancer laterality was studied in relation to age in 80,784 cases of invasive and 3,835 cases of pre-invasive breast cancer in women and 548 cases of invasive breast cancer in men reported to the Swedish Cancer Registry, 1970-89. In a subset of 11,274 women with invasive disease, data on parity were available through the Swedish Fertility Registry. Laterality also was evaluated in relation to age and reproductive variables in 3,986 cases from an international study from the 1960s. The overall incidence of pre-invasive and invasive cancer was higher in the left than in the right breast among both women and men. The excess incidence of invasive cancer in the left breast was evident only after the age of 45 years in women; a similar phenomenon may exist with pre-invasive disease in women and in men. The age-dependent laterality pattern did not appear to be confounded by menopausal status. Among women younger than 45 years, nulliparity, right handedness, and late age at menarche was associated with a somewhat higher incidence of cancer in the right breast. The laterality findings are likely to be due to factors operating early in the carcinogenic process, perhaps at the pre-initiation stage.

Adult↗
PubMed1994

Risk factors for colorectal cancer in patients with ulcerative colitis: a case-control study.

BACKGROUND/AIMS: The risk of colorectal cancer increases in patients with ulcerative colitis, most markedly among young patients and/or those with extensive disease at onset. However, it is unknown whether individual risk can be predicted more precisely and whether cancer risk can be reduced by long-term treatment with sulfasalazine. METHODS: In a population-based cohort of 3112 patients with ulcerative colitis, we compared 102 cases of colorectal cancer and 196 matched controls without cancer. Hospital records were used to abstract information on pharmacological therapy, disease activity, and extraintestinal manifestations. The relative risk (RR) of cancer was estimated by conditional logistic regression. RESULTS: Pharmacological therapy, especially sulfasalazine, lasting at least 3 months was associated with a significant protective effect (RR, 0.38; 95% confidence interval [CI], 0.20-0.69) independent of disease activity. There was also a tendency to an independent protective effect for cigarette smoking (RR, 0.15; 95% CI, 0.02-1.25) and higher disease activity (RR, 0.80; 95% CI, 0.49-1.33). CONCLUSIONS: The risk of colorectal cancer among patients with ulcerative colitis can be reduced through pharmacological therapy. This finding is consistent with the reports of a protective effect of aspirin among individuals in the general population.

Adolescent↗
PubMed1994

Dual effect of parity on breast cancer risk.

This study examined whether breast cancer risk increased for a short period after childbirth, but decreased after a longer period of time. Data from an international case-control study on breast cancer conducted in the 1960s were used to study the modifying effect of age at enrolment on the relationship between parity and breast cancer risk, comparing first uniparous with nulliparous women, and then biparous versus uniparous women. The statistical analysis was performed by modelling through multiple logistic regression, adjusting for study site, age at menarche, menopausal status and obesity index. Comparing uniparous with nulliparous women, an early age at birth seems to be protective for all periods after birth, whereas a late age at birth imparts a higher risk than nulliparity in the period immediately after birth, which declines with the passage of time. The modification effect by age was not apparent when biparous women with different age at second birth were compared with uniparous women. The results support the hypothesis that pregnancy oestrogens impart a transient increase of maternal breast cancer risk when the full-term pregnancy occurs late in a woman's life.

Adult↗