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Biomedical subjects

A Ekbom

Publications and source records attributed to A Ekbom.

At least 181 records · Page 10Linked to original sources
PubMed1996

Seasonal variations in the onset of ulcerative colitis.

Several retrospective studies have reported seasonal variations in the relapse of ulcerative colitis, and two studies have found seasonality in the onset of ulcerative colitis, with a peak from August to January. This study was designed to investigate possible seasonal variations of onset of ulcerative colitis (UC) and Crohn's disease (CD). Patients with symptoms of one year or less were recruited from a prospective study of the incidence of inflammatory bowel disease, and the onset of symptoms was recorded month by month for four consecutive years. A total of 420 patients with UC and 142 patients with CD were included. There was monthly seasonality (p = 0.028) in symptomatic onset in December and January for UC but not for CD. It was found that environmental agents with known seasonality can be of importance for the seasonal variations of disease onset in UC.

Adult↗
PubMed1996

Incidence of Crohn's disease in four counties in southeastern Norway, 1990-93. A prospective population-based study. The Inflammatory Bowel South-Eastern Norway (IBSEN) Study Group of Gastroenterologists.

BACKGROUND: Standardized criteria for Crohn's disease (CD) have only recently been developed, and prospective community-based incidence studies have been performed only during the past 3 decades. Geographic variations in incidence may therefore be due to differences in study design. METHODS: From 1 January 1990 to 31 December 1993 all new cases of CD in four counties in southeastern Norway were prospectively registered. RESULTS: A total of 225 new cases yielded an annual incidence of 5.8/10(5), with the highest incidence in mixed rural-urban areas. A peak of 11.2/10(5) in the annual incidence was found for the age group 15 to 24 years, with no significant differences in the overall annual incidence by gender. An average duration of 6 months of disease before diagnosis was unchanged during the 4 years. About half of the patients had isolated colonic disease, and one-quarter had isolated small-bowel disease. CONCLUSIONS: This study confirms the high incidence figures for Scandinavia, with a particularly high incidence in mixed rural-urban areas. Ileocolonoscopy improves the accuracy of the diagnosis and of the determination of disease extent, which may have therapeutic implications for the treatment and follow-up of patients.

Adolescent↗
PubMed1996

Incidence of ulcerative colitis and indeterminate colitis in four counties of southeastern Norway, 1990-93. A prospective population-based study. The Inflammatory Bowel South-Eastern Norway (IBSEN) Study Group of Gastroenterologists.

BACKGROUND: The incidence of ulcerative colitis (UC) has been difficult to interpret because prospective studies have only been performed during the past 3 decades. Geographic variations may therefore be due to differences in study design. METHOD: From 1 January 1990 to 31 December 1993 all new cases of UC in four counties in southeastern Norway were prospectively registered. Cases diagnosed as indeterminate colitis (IND) when endoscopy and histopathology were inconclusive or diverged with regard to diagnosis of UC or Crohn's disease (CD) were also included in the study. RESULTS: A total of 525 cases of UC and 93 cases of IND yielded an mean annual incidence of 13.6/10(5) and 2.4/10(5), respectively. There were differences in incidence between counties, and a peak of 21.5/10(5) in the annual incidence was found for the age group 25 to 34 years in UC. The distribution was about equal for each of the groups proctitis and left-sided and extensive colitis. The time interval from onset of symptoms to diagnosis was 4 months. CONCLUSION: In this study one of the highest incidences of UC in the world has been found. The classification 'indeterminate colitis' seems reasonable to use in some of the cases to prevent misclassification at the initial stage of diagnosis.

Adolescent↗
PubMed1996

Breast size and mammographic pattern in relation to breast cancer risk.

The relation of Wolfe's parenchymal patterns and radiographically-assessed breast size with breast cancer risk was evaluated in a population-based nested case-control study in Uppsala, Sweden. All women who attended a mammographic screening programme in Uppsala county starting in 1988 have been followed for the occurrence of breast cancer through 1993. The analysis was based on 295 cases and 589 age-matched controls, whose mammograms were blindly evaluated for parenchymal pattern and breast size. Women with P2 or DY pattern had a significantly elevated risk of breast cancer compared with women with N1 or P1 (OR = 2.09; 95% CI = 1.52-2.86). There was an inverse association of breast size with breast cancer risk, which disappeared after adjusting for parenchymal pattern, because breasts of smaller size tended to have high-risk parenchymal patterns. It is concluded that in Swedish women, and perhaps in Caucasian women in general, small breast size is associated with increasing breast risk through its association with high-risk parenchymal pattern. This is in contrast to the fact that Asian women, who in general have breasts of smaller size, have low prevalence of high-risk parenchymal pattern as well as low rates of breast cancer.

Adult↗
PubMed1996

Reproductive history and cigarette smoking as risk factors for thyroid cancer in women: a population-based case-control study.

A population-based case-control study was conducted in Northern Norway and Central Sweden to investigate hormonal and reproductive factors and cigarette smoking as determinants of papillary and follicular thyroid carcinoma in women. Information on 191 histologically confirmed cases and 341 age-matched controls was included. No clear association was found with regard to the number of live births, number of pregnancies, a history of incomplete pregnancies, or the use of oral contraceptives or hormonal replacement therapy. However, an early first childbirth (before 20 years of age, or less than 5 years after menarche) was associated with an increased risk of thyroid cancer. There was an increased risk of thyroid cancer among women with a history of artificial menopause compared to those with a spontaneous menopause [odds ratio (OR), 2.52; 95% confidence interval (CI), 0.96-6.62], which was more pronounced for the papillary carcinoma and after adjustment for age at menopause and use of replacement therapy. Cigarette smokers had a decreased risk of borderline statistical significance compared to nonsmokers (OR, 0.69; 95% CI, 0.47-1.01), particularly among premenopausal women (OR, 0.60; 95% CI, 0.38-0.96). This negative association persisted after adjustment for parity, hormonal treatments, and education. Women who started smoking before the age of 15 experienced a marked reduction in risk (OR, 0.38%; 95% CI, 0.18-0.80¿). Moreover, there was a suggestion of a dose-response effect with the amount of cigarettes smoked daily and with duration of the habit. Both the increased risk of artificial menopause and the negative association with smoking are compatible with a relation between levels of estrogens and thyroid cancer among women.

Adenocarcinoma, Follicular↗
PubMed1995

Medical diagnostic x rays and thyroid cancer.

BACKGROUND: Diagnostic x rays are the largest man-made source of exposure to ionizing radiation for the general population. Whether there are meaningful cancer risks associated with such exposures is unclear. Most previous case-control studies have relied on recalled histories of x rays, and there is concern that completeness and accuracy of recall might differ between cancer case and control subjects. PURPOSE: The present study used information recorded prospectively in hospital charts to address the relationship between medical diagnostic x rays and risk of thyroid cancer. METHODS: The Swedish Cancer Registry and the Uppsala-Orebro Regional Cancer Registry were used to identify persons with papillary or follicular thyroid cancer diagnosed from January 1, 1980, through December 31, 1992, among residents of the Uppsala Health Care Region. After histopathologic review, there were 484 such case subjects available for study. An equal number of age-, sex-, and county of residence-matched control subjects from the general population were randomly selected on the basis of the Swedish Registry of the Total Population. Lifetime residential histories were compiled, and radiology records were searched at all Swedish hospital serving regions where study subjects ever maintained an official residence. Approximate radiation doses to the thyroid gland for specific types of x-ray examinations were assigned on the basis of mean values of measurements made in Sweden in 1973-1975 and in the United States in 1970. Odds ratios were used to evaluate the association between diagnostic radiography and risk of thyroid cancer. RESULTS: A total of 3853 medical diagnostic x rays were ascertained among thyroid cancer case subjects and 4039 among the matched control subjects. There were no tendency for case subjects to have had more of the types of x-ray procedure associated with higher radiation dose to the thyroid gland (i.e., those involving the head or neck area). This finding was true even when analysis was restricted to x rays occurring before 1960, when doses likely were higher than in more recent years, and for examinations occurring in childhood and adolescence, when susceptibility to radiation-induced thyroid cancer is greatest. The relative risk of thyroid cancer was not significantly associated with estimated cumulative dose to the thyroid gland from diagnostic x rays (two-sided P for trend = .80). CONCLUSION: These data indicate that the risk of thyroid cancer due to medical diagnostic x rays, if any, is very small.

Adenocarcinoma, Follicular↗
PubMed1995

The risk of esophageal cancer in patients with achalasia. A population-based study.

OBJECTIVE: To determine more precise and accurate cancer risk estimates for achalasia that could be used to plan surveillance. DESIGN: Cohort. SETTING: Swedish population. PARTICIPANTS: All patients with achalasia listed in the population-based Swedish Inpatient Register from 1964 through 1989. MAIN OUTCOME MEASURES: The observed number of cancers in the cohort was compared with expected numbers of cancers (standardized incidence ratio [SIR]) for each 5-year age group and calendar year of observation, calculated using data from the Swedish Cancer Registry. RESULTS: A total of 1062 patients with achalasia accumulated 9864 years of follow-up. The mean age at entry was 57.2 years, and the mean age at cancer diagnosis was 71.0 years. Esophageal cancer occurred in 24 patients. The risk of esophageal cancer in the first year after achalasia diagnosis was extremely high (SIR, 126.3; 95% confidence interval [CI], 63.0 to 226.1) as a consequence of prevalent cancers leading to distal esophageal obstruction simulating achalasia. During years 1 to 24, the risk was increased more than 16-fold (SIR, 16.6; 95% CI, 8.8 to 28.3). Annual surveillance after the first year would require 406 endoscopic examinations in men and 2220 in women to detect one cancer. CONCLUSIONS: Patients with achalasia are at markedly increased risk of developing esophageal cancer. A substantial number of surveillance examinations might be required to screen for cancers, especially in women. It is not known whether surveillance will result in improved survival.

Adult↗
PubMed1995

Prenatal and neonatal risk factors for childhood lymphatic leukemia.

BACKGROUND: Because the incidence of childhood acute lymphatic leukemia peaks between 2 and 4 years of age, the risk factors may exert their influence during the prenatal and/or the neonatal periods. Results of previous studies of perinatal risk factors have been contradictory, perhaps because most studies either have been hospital based or have been restricted to limited geographical areas. PURPOSE: A nationwide case-control study was carried out to identify maternal and perinatal risk factors for this disease. METHODS: The case-control study was nested in cohorts defined by all live births in Sweden recorded in the nationwide Medical Birth Register. Since 1973, this register has routinely collected information on all hospital births in regard to maternal demographic data, reproductive history, pregnancy, delivery, and the neonatal period. From the Swedish National Cancer Register, 613 case subjects were identified in successive birth cohorts from 1973 through 1989. Five control subjects per case subject were randomly selected from the pool of children matched by sex and month and year of birth. Conditional logistic regression was used to calculate the odds ratios (ORs) and 95% confidence intervals (CIs) for potential risk factors and to estimate their effects after adjustment for possible confounders. RESULTS: Risk of childhood lymphatic leukemia at all ages increased with Down's syndrome (OR = 20.0; 95% CI = 4.2-94.2), maternal renal disease (OR = 4.4; 95% CI = 1.6-12.1), use of supplementary oxygen (OR = 2.3; 95% CI = 1.5-3.6), postpartum asphyxia (OR = 1.8; 95% CI = 1.2-2.6), birth weight of more than 4500 g (OR = 1.7; 95% CI = 1.1-2.7), and hypertensive disease during pregnancy (OR = 1.4; 95% CI = 1.0-1.9). Down's syndrome affected risk mostly in children younger than 5 years, whereas other factors affected those children 5 years old or older. Being one of a multiple birth also increased risk among older children (OR = 2.5; 95% CI = 1.0-6.0). Use of supplementary oxygen may act as a causal intermediate (surrogate) for postpartum asphyxia and its causes, as would high birth weight for its causes. CONCLUSIONS: Several maternal and perinatal risk factors were found to be associated with childhood lymphatic leukemia, but they showed age-specific differences. Overall, only a few risk factors were identified, and these accounted for a small proportion of cases. We concluded that most risk factors for childhood lymphatic leukemia remain unidentified in very young children.

Case-Control Studies↗
PubMed1995

Is residence in areas of endemic goiter a risk factor for thyroid cancer?

The association between an indicator of iodine deficiency and differentiated thyroid cancer has been investigated in a population-based case-control study. This included all incident cases (N = 484) of papillary and follicular thyroid cancer diagnosed during the years 1980-1992 in a Swedish Health Care Region among residents born in Sweden, and as many individually matched controls. Cases were included after a uniform review of their histopathological specimens. Residence in areas where goiter had been severely endemic in the 1930s was used as exposure indicator. Odds ratios (OR) and 95% confidence intervals as estimates of relative risk were calculated as a measure of association using logistic regression. A trend toward an association was found with a duration of residence in goiter areas between 21 and 40 years, most prominent among follicular cancer cases and in the group diagnosed at age > or = 50 years compared to not exposed. Exposure for the first time during adolescence (between 11 and 20 years) was associated with an increased risk of papillary cancer. This was especially evident among women, both when compared to not exposed and to those exposed during the first year of life; the association was strengthened after adjustment for duration of residence. These findings support the hypothesis of distinct causation patterns from iodine deficiency to the 2 most common histological types of thyroid cancer.

Adolescent↗
PubMed1995

Perinatal characteristics and adult mammographic patterns.

We retrieved breast mammograms for 370 women 40 to 74 years old with no history of breast cancer, for whom birth weight, birth length, placental weight and other birth characteristics were indicated in their standard birth records at the Uppsala University Hospital. Blind evaluation of the mammograms allowed these to be classified according to Wolfe's pattern. Logistic regression analysis was applied using as independent variables the recorded birth characteristics and as outcome variable, high risk (P2 and DY) versus low risk (N1 and P1) mammographic parenchymal pattern. After controlling for all the recorded variables, the odds ratio for a high-risk pattern (P2 or DY) increased consistently and significantly (P for trend 0.02) with the weight of the placenta, i.e. the main estrogen-producing organ during pregnancy. There were weak and non-significant positive associations with increasing birth weight (P for trend 0.53) and birth length (P for trend 0.52). These results are compatible with hypotheses suggesting that pregnancy estrogens or other perinatal characteristics may play a risk-modulating role influencing breast cancer in the offspring.

Adult↗
PubMed1995

Abortion and the risk of breast cancer: a case-control study in Greece.

We have examined the association between induced or spontaneous abortion and breast cancer risk in Greece. In a hospital-based case-control study in Athens, 820 patients with confirmed breast cancer were compared with 795 orthopedic patient controls and 753 healthy visitor controls, matched to cases by age and interviewer. Logistic regression was used to analyze the data, controlling for demographic, reproductive and nutritional variables. Odds ratio (OR) patterns were similar for the 2 control series, which were therefore combined to increase precision of the estimates. The risk for breast cancer was not increased for women who had a history of abortion, compared to nulliparous women with no history of abortion. Thus ORs and 95% confidence intervals were for nulliparous women with spontaneous abortion, 1.17 (0.64-2.13); for nulliparous women with induced abortion, 0.98 (0.56-1.73); for parous women with no abortion, 0.56 (0.31-1.01); for parous women with spontaneous abortion, 0.61 (0.33-1.14) and for parous women with induced abortion, 0.99 (0.56-1.74). When the analysis was restricted to parous women, using parous women with no history of abortion as the baseline, ORs and 95% confidence intervals were for induced abortion before first full-term pregnancy, 2.06 (1.45-2.90); for induced abortion after first full-term pregnancy, 1.59 (1.24-2.04) and for spontaneous abortion, 1.10 (0.82-1.40). Our findings suggest that an interrupted pregnancy does not impart the long-term protective effect of a full-term pregnancy attributable to terminal differentiation.

Abortion, Induced↗
PubMed1995

Cancer risk after hip replacement with metal implants: a population-based cohort study in Sweden.

BACKGROUND: Joint replacement with metal implants has been the standard procedure for surgical treatment of irreversible degeneration of hip and knee joints for more than two decades. However, reports of local malignancy after joint replacement and experimental studies that suggest a carcinogenic action of metal ions and polymethylmethacrylate (an acrylic compound used to stabilize the implant in the host) have raised concern about the possible long-term risks associated with metal implants. PURPOSE: Our aim was to study cancer risk in a Swedish cohort of patients who had hip replacement surgery during the period 1965 through 1983. METHODS: We studied the risk of cancer in a cohort of 39 154 patients (14 869 men and 24 285 women), identified in the nationwide Swedish Inpatient Register with at least one hip replacement during the period 1965 through 1983. The patients were followed through 1989 by means of record linkage to the Swedish Cancer Register. The cohort contributed a total of 327 922 person-years at risk. Standardized incidence ratios (SIRs) were computed using age-, sex-, and period-specific incidence rates derived from the entire Swedish population. RESULTS: The overall relative risk of cancer was increased by only 3%. Bone cancer--the focus of previous concerns--occurred in six cases versus 4.3 expected, and connective tissue cancer occurred in 28 cases versus 25.9 expected. Increased risks were observed for kidney cancer (SIR = 1.31; 95% confidence interval [CI] = 1.13-1.51), prostate cancer (SIR = 1.13; 95% CI = 1.04-1.22), and melanoma (SIR = 1.23; 95% CI = 1.00-1.50). The relative risk of gastric cancer steadily declined with increasing follow-up time, in both men and women (SIR = 0.58; 95% CI = 0.39-0.84 more than 10 years after hip replacement). CONCLUSION: In this study, the largest study to date to evaluate hip replacement and subsequent cancer risk, the overall cancer risk appears to be negligible from a public health perspective, and our results have not produced any strong evidence against the continued use of these devices. Nevertheless, the small but statistically significant increases in kidney and prostate cancers and the decrease in gastric cancer deserve further study.

Aged↗