Low birth weight, family history of diabetes, and glucose intolerance in Swedish middle-aged men.

OBJECTIVE: To investigate the association between low birth weight and glucose intolerance in relation to family history of diabetes. RESEARCH DESIGN AND METHODS: We conducted a population-based cross-sectional study of 2,237 men born in 1938-1957 in four municipalities in the outskirts of Stockholm, 50% of whom had a family history of diabetes (at least one first-degree or two second-degree relatives with diabetes). Oral glucose tolerance testing detected 35 cases of type 2 diabetes, 102 cases of impaired glucose tolerance, and 57 cases of impaired fasting glucose. RESULTS: In subjects without a family history of diabetes, low (< or = 3,000 g) birth weight was associated with an odds ratio of 2.3 (95% confidence intervals = 0.4-14.4) for diabetes, 1.8 (0.7-4.3) for impaired glucose tolerance, and 3.3 (1.0-10.4) for impaired fasting glucose. In subjects with a family history of diabetes, the corresponding figures were approximately similar, except for diabetes, for which the odds ratio was 5.4 (2.0-14.9). For men with low birth weight in combination with a family history of diabetes, the odds ratio was 10.9 (2.9-41.2) for diabetes, 2.4 (1.1-5.6) for impaired glucose tolerance, and 5.9 (2.1-16.3) for impaired fasting glucose. CONCLUSIONS: This study indicated that low birth weight is associated with type 2 diabetes, impaired glucose tolerance, and impaired fasting glucose in men. This finding was most pronounced in subjects with diabetes in the family, but it was also indicated in those without a family history of diabetes. Men with the combination of low birth weight and family history of diabetes seem to be at particularly high risk of developing type 2 diabetes.

Relative risk is a relevant measure of association of left-handedness with inflammatory bowel disease.

A study of inflammatory bowel diseases and left-handedness was published in this Journal by Searlman and Fugagli (1987). We reanalysed the data and found that left-handedness was associated with relative risk of 2.5 for Crohn's disease and 2.9 for ulcerative colitis.

Use of oral moist snuff and inflammatory bowel disease.

We examined the association between oral moist snuff use and inflammatory bowel disease in a case-control study based on the population in Stockholm County. The relative risk (RR) associated with ever use of moist snuff was 2.1 (95% CI: 1.0-4.6) for Crohn's disease, and 2.2 (95% CI: 1.1-4.4) for ulcerative colitis. Cigarette smoking indicated a synergistic relation with moist snuff: the RR estimate of Crohn's disease was 3.7 (95% CI: 1.1-13.1) and of ulcerative colitis 3.3 (95% CI: 1.0-10.9) for snuff dippers who were also current cigarette smokers, but only 0.9 and 1.1 respectively for snuff dippers who had never smoked.

Retrospective versus original information on diet: implications for epidemiological studies.

The aim of this study was to evaluate the use of retrospective information on diet in relation to the information originally reported. Hospital controls (n = 131) who participated in a case-control study on diet and pancreatic cancer in Stockholm, Sweden, answered a second postal questionnaire four years later about their current and previous food consumption. The food consumption was dichotomized for the purpose of the analysis. In relation to the original information, the use of retrospective information overestimated previous food consumption among subjects with increased intake, while retrospective information underestimated previous food consumption among subjects with decreased intake. These tendencies were slightly more pronounced in the age group 60-79 years than in the age group 40-59 years. For subjects with unchanged food consumption, there was a high agreement between original and retrospective information. Considerable differential misclassification could be introduced in an epidemiological study if cases and non-cases differ with regard to changes in food consumption.

Risk indicators for inflammatory bowel disease.

We investigated the association between different risk indicators and inflammatory bowel disease in a case-control study based on the population of Stockholm County during 1980-1984. Information on physical activity, oral contraceptives, some previous diseases and childhood characteristics was collected using a postal questionnaire for 152 cases of Crohn's disease, 145 cases of ulcerative colitis, and 305 controls. The relative risk (RR) of Crohn's disease was inversely related to regular physical activity and estimated at 0.6 (95% CI: 0.4-0.9) and 0.5 (95% CI: 0.3-0.9) for weekly and daily exercise, respectively. Having psoriasis prior to the inflammatory bowel disease was associated with an increased relative risk of Crohn's disease (RR = 2.9, 95% CI: 1.1-7.9). Use of oral contraceptives was associated with an increased RR of 1.7 for both Crohn's disease and ulcerative colitis. Crohn's disease confined to the colon and total ulcerative colitis at diagnosis were most strongly associated with oral contraceptives.

Effect of prefracture versus postfracture dietary assessment on hip fracture risk estimates.

BACKGROUND: Dietary factors are presumed to have influence on bone mass and hence fracture susceptibility. Most information in this respect is based on retrospective assessment of previous dietary habits. In a population-based case-control study nested within a cohort, we collected dietary information both before and after a first hip fracture. Thus it was possible to study reported changes in dietary habits, intentional as well as unintentional, among hip fracture patients after a first hip fracture and to compare postfracture with prefracture dietary information. METHODS: More than 65 000 women born 1914-1948 in two counties in central Sweden completed a food frequency questionnaire regarding their usual current dietary habits, before attending a mammographic screening between the years 1987 and 1990. Subsequently 123 of them sustained a first hip fracture and were defined as cases in the present study. For every case, one control, individually matched by age and county of residence, was selected from the cohort. A second identical food frequency questionnaire was mailed to both cases and controls on average 2 years after the hip fracture event. In total 98 case/control pairs could be included in the analysis. The association between diet and hip fracture was evaluated and the results from the two dietary assessments were contrasted. Women who themselves claimed that they had not changed their diet in recent years were analysed separately. RESULTS: The hip fracture cases, compared with the controls, had reduced their reported dietary intake of dairy products after the fracture. Apparently this was not intentional since this effect was more pronounced among those cases who claimed that their diet was unchanged. The changes were most apparent among the younger cases with a more recent hip fracture and with a body mass index above the median. Half of the cases, more than twice the frequency in controls, who were initially classified as having high intake of dairy products were classified as having low intake (<800 mg calcium/day) after the hip fracture. This also lowered, in fact reversed, the relative risk estimates of hip fracture both for intake of dairy products and calcium. Crude odds ratios of highest quartile of intake versus lowest, changed from 3.0 to 0.6 for dairy products and from 2.6 to 0.9 for calcium. No other foods or nutrients displayed such notable differences between the two surveys. CONCLUSION: We conclude that the use of current and retrospective dietary information after a hip fracture can lead to a differential misclassification in dietary studies and to biased estimates of hip fracture risk as compared with prospectively collected dietary information.

Physical activity and hip fracture: a population-based case-control study. Swedish Hip Fracture Study Group.

BACKGROUND: A growing body of literature suggests that physical activity may be a protective factor against hip fracture. METHODS: To study the association between hip fracture risk and recreational physical activity at various ages, changes in activity during adult life, occupational physical activity and how risks vary by adult weight change, we performed a population-based case-control study among postmenopausal women aged 50-81 years residing in six counties in Sweden in 1993-1995. The analysis consisted of 1327 women with hip fracture and 3262 randomly selected controls. Information on leisure physical activity before age 18, at 18-30 years and during recent years was based on a questionnaire. Data on occupational physical activity were collected through an independent classification of job titles obtained from record linkage with census data from 1960, 1970 and 1980. RESULTS: There was a protective effect of recent leisure physical activity. Compared to women who reported no leisure activity, the odds ratios (OR) were 0.79 (95% CI: 0.62-1.00), 0.67 (95% CI: 0.54-0.84) and 0.48 (95% CI: 0.39-0.60) for women who exercised <1 h per week, 1-2 h per week, and 3+ h per week, respectively. These decreased OR were more pronounced in women who had lost weight after 18 years of age than in those who had gained weight. Women with high physical activity at both 18-30 years and during recent years did not have a stronger protection than those with isolated high activity late in life, after accounting for recent activity. Occupational physical activity was not associated with hip fracture risk in this study. CONCLUSIONS: Recent physical activity is protective against hip fracture. The protective effect is most pronounced in women who had lost weight after age 18.

Evaluation of surveillance programmes for colorectal cancer in ulcerative colitis patients by case-control studies: methodological considerations.

OBJECTIVES: The evaluation of the efficacy of colonoscopy screening in patients with ulcerative colitis for colorectal cancer is associated with methodological difficulties. Case-control studies can, however, be used to determine the efficacy of such a programme and the outline of the methodology in such a programme is presented. METHODS: The randomised controlled trial provides perspective for case-control studies of screening efficacy. Cases are selected from persons who have ulcerative colitis with manifestations of colorectal cancer: for example, those who have died of colorectal cancer or have symptomatic metastases. Controls are selected from persons who have ulcerative colitis, who had been alive when the case died of colorectal cancer, and who had been subject to the risk of dying from, but had not had, colorectal cancer diagnosed when the case was diagnosed with colorectal cancer. The relevant screening history for cases begins with the case's diagnosis of ulcerative colitis and ends with the cases diagnosis of colorectal cancer; that for controls should be comparable to that for cases to avoid bias. Cases and controls are compared with respect to their "exposure" to colonoscopy during their screening histories: the occurrence of any screening, which took place during the period of time that an occult tumour (or an identifiable lesion) may plausibly have been present. CONCLUSION: The proposed methodology can evaluate the efficacy of a screening programme rapidly, practically, and ethically.

Hormone replacement therapy and risk of hip fracture: population based case-control study. The Swedish Hip Fracture Study Group.

OBJECTIVE: To determine the relative risk of hip fracture associated with postmenopausal hormone replacement therapy including the effect of duration and recency of treatment, the addition of progestins, route of administration, and dose. DESIGN: Population based case-control study. SETTING: Six counties in Sweden. SUBJECTS: 1327 women aged 50-81 years with hip fracture and 3262 randomly selected controls. MAIN OUTCOME MEASURE: Use of hormone replacement therapy. RESULTS: Compared with women who had never used hormone replacement therapy, current users had an odds ratio of 0.35 (95 % confidence interval 0.24 to 0.53) for hip fracture and former users had an odds ratio of 0.76 (0.57 to 1.01). For every year of therapy, the overall risk decreased by 6% (3% to 9%): 4% (1% to 8%) for regimens without progestin and 11% (6% to 16%) for those with progestin. Last use between one and five years previously, with a duration of use more than five years, was associated with an odds ratio of 0.27 (0.08 to 0.94). After five years without hormone replacement therapy the protective effect was substantially diminished (-7% to 48%). With current use, an initiation of therapy nine or more years after the menopause gave equally strong reduction in risk for hip fracture as an earlier start. Oestrogen treatment with skin patches gave similar risk estimates as oral regimens. CONCLUSIONS: Recent use of hormone replacement therapy is required for optimum fracture protection, but therapy can be started several years after the menopause. The protective effect increases with duration of use, and an oestrogen-sparing effect is achieved when progestins are included in the regimen.

Do left-handers have increased mortality?

To study the association between handedness and mortality, we evaluated the experience of a Swedish population-based cohort comprising 48,964 conscripts age 18-21 years in 1969-1970. We linked this cohort to the Cause-of-Death Register through 1989. Hand preference was measured by a simple question regarding handedness; to confirm the answer, the conscript held a dummy rifle while an observer recorded whether he was a left- or right-hand shooter. A total of 954 deaths occurred in the cohort, of which 82 were among left-handers, corresponding to a relative risk estimate of 1.0 (95% confidence interval = 0.8-1.3) for left-handers compared with right-handers. The relative risk estimate of death by motor vehicle accidents was 1.3 (95% confidence interval = 0.8-2.0). The data in this study refute previous reports indicating an increased overall mortality. The results regarding motor vehicle death indicate a slightly increased relative risk associated with left-handedness.

Failed Christiansen total hip arthroplasty. A radiographic and histologic study.

Twenty-two consecutive cases of the Christiansen total hip arthroplasty revised because of aseptic loosening were analyzed with regard to radiographic changes and operative and histopathologic findings. This prosthesis was designed with a socket and a trunnion sleeve made of polyoxymethylene or Delrin. In 18 cases there was isolated socket loosening, in all cases there was obvious bone resorption beneath the collar of the stem, and in 20 cases the socket had migrated. The radiographic socket wear rate averaged 0.4 mm/year. In 18 cases a significant amount of debris material was found in the joint cavity. Light microscopy revealed a severe foreign body reaction with numerous plastic particles, most often engulfed by macrophages. Taken together, these findings indicate that socket wear leading to a foreign body reaction with bone resorption is the main cause of the poor results noted with this particular total hip prosthesis.

Retrospective versus original information on cigarette smoking. Implications for epidemiologic studies.

This study was conducted to evaluate the agreement between retrospective information on cigarette smoking and original information obtained six years previously. A questionnaire on smoking habits was answered by 94% of a random sample of the adult Swedish population in 1963 (original information). Of the 10,356 subjects aged 40-59 years who reported that they had ever smoked regularly, 9,394 answered a second questionnaire in 1969. Information was obtained on present smoking habits as well as on smoking habits in 1963 (retrospective information). Cigarette consumption was divided into four categories: 0, 1-7, 8-15, and 16+ cigarettes per day. In relation to the original information on smoking, retrospective information showed a strong tendency to overestimate previous cigarette consumption among subjects who had increased their cigarette smoking (69%), and to underestimate previous cigarette consumption among subjects who had decreased their cigarette smoking (49%). Subjects with unchanged cigarette consumption showed a high level of agreement between original and retrospective information (89%). Age, sex, income, and occupational status also had some impact on the agreement between retrospective and original information on cigarette consumption. Consequences for epidemiologic studies based on retrospective smoking information are discussed. The use of retrospective information may introduce considerable differential misclassification when cases and noncases differ with regard to changes in smoking habits.

Diet and inflammatory bowel disease: a case-control study.

We conducted a population-based case-control study of inflammatory bowel disease and dietary habits in Stockholm during 1984-1987. We obtained retrospective information about food intake 5 years previously by a postal questionnaire for 152 cases with Crohn's disease, 145 cases with ulcerative colitis, and 305 controls. The relative risk of Crohn's disease was increased for subjects who had a high (55 gm or more per day) intake of sucrose (relative risk = 2.6, 95% confidence interval = 1.4-5.0) and was decreased for subjects who had a high (15 gm or more per day) intake of fiber (relative risk = 0.5, 95% confidence interval = 0.3-0.9). The most striking finding was an increased relative risk of both Crohn's disease and ulcerative colitis associated with consumption of fast foods: the relative risk associated with consumption of fast foods at least two times a week was estimated at 3.4 (95% confidence interval = 1.3-9.3) for Crohn's disease and 3.9 (95% confidence interval = 1.4-10.6) for ulcerative colitis. Although coffee seemed to provide a protective effect for both diseases, there are reasons to consider this finding an artifact.

Factors affecting colectomy rate in ulcerative colitis: an epidemiologic study.

Factors affecting colectomy rate were studied in a retrospective population based series of 1586 patients with ulcerative colitis, in Stockholm County during 1955-84. Five hundred and sixty eight patients (36%) had total colitis at diagnosis, 603 patients (38%) left sided colitis, and 397 patients (25%) proctitis. During a median period of observation of 13 years 514 patients were treated by colectomy. The five, 10, and 25 year cumulative colectomy rate were 20% (CI 18-22%), 28% (CI 26-30%), and 45% (CI 41-49%) respectively. The main factor affecting the colectomy rate was the extent of disease at diagnosis. Patients with total colitis showed a five, 10, and 25 year cumulative colectomy rate of 32% (CI 28-36%), 42% (CI 38-46%), and 65% (CI 58-72%) respectively. Ten per cent of the 1586 patients had a colectomy during the first year after diagnosis, 4% during the second year and 1% during subsequent years. The age at diagnosis and sex did not affect the cumulative colectomy rate. Elective colectomy was performed in 322 cases (63%) and acute colectomy in 192. The duration of disease before colectomy fell during the study period due to a more standardised criteria for colectomy in severe attacks. One hundred and twenty nine (66%) of the acute colectomies were performed within two years from diagnosis.

Inflammatory bowel disease and tobacco smoke--a case-control study.

A case-control study was carried out in Stockholm, Sweden between 1984 and 1987 to evaluate the association of cigarette smoking and exposure to environmental tobacco smoke during childhood and the subsequent development of inflammatory bowel disease. Information on smoking was obtained by a postal questionnaire. The relative risk of Crohn's disease in current smokers compared with those who had never smoked was 1.33 (95% confidence limits 0.7; 2.6) in men and 4.99 (2.7; 9.2) in women; the corresponding results for ulcerative colitis were 0.96 (0.5; 1.8) and 0.72 (0.4; 1.4). The relative risk of ulcerative colitis in recent exsmokers compared with those who had never smoked was 2.18 (0.9; 5.0). Furthermore, an increase in the risk of Crohn's disease was found in those who were exposed to environmental tobacco smoke during childhood, the relative risk being 1.50 (1.0; 2.3). The corresponding relative risk of ulcerative colitis was 0.98 (0.6; 1.5).

Risk factors for sudden unexpected death in epilepsy: a case-control study.

BACKGROUND: Sudden unexpected death is substantially more common in people with epilepsy than in the general population. Our objective was to investigate the association between some clinical variables and sudden unexpected death in epilepsy (SUDEP) to identify risk factors. METHODS: This nested case-control study was based on a cohort of people aged between 15 and 70 years, who, during 1980-89, had been admitted to and discharged with a diagnosis of epilepsy from any hospital in the county of Stockholm. The study population was followed up through the National Cause of Death Register until Dec 31, 1991. Cases were individuals who had died, with a diagnosis of epilepsy registered on the death certificate, and who after review of medical and necropsy records were found to meet our SUDEP criteria. Three control participants, who were living epilepsy patients matched for age and sex, were selected from the same cohort for each case. All medical records were examined. Clinical data were collected and analysed on a predesigned protocol. FINDINGS: 57 SUDEP cases were included, of whom 91% had undergone necropsy. The relative risk of SUDEP increased with number of seizures per year. The estimated relative risk was 10.16 (95% CI 2.94-35.18) in patients with more than 50 seizures per year, compared with those with up to two seizures per year. The risk of SUDEP increased with increasing number of antiepileptic drugs taken concomitantly--9.89 (3.20-30.60) for three antiepileptic drugs compared with monotherapy. Other major risk factors were early-onset versus late-onset epilepsy (7.72 [2.13-27.96]), and frequent changes of antiepileptic drug dosage compared with unchanged dosage (6.08 [1.99-18.56]). The association between SUDEP risk and early onset, and SUDEP risk and seizure frequency, was weaker for female than for male patients, whereas frequent dose changes showed a stronger association in female patients. INTERPRETATION: Our data suggest that SUDEP is a seizure-related event, although the pathophysiological substrate that predisposes individuals to SUDEP may be established at an early age, and there may be some sex differences. Improvement of seizure control and possibly the avoidance of polytherapy may be ways to reduce the risk of SUDEP.

Exposure to stainless steel welding fumes and lung cancer: a meta-analysis.

Stainless steel welding is associated with exposure to metals including hexavalent chromium and nickel. This study is a meta-analysis of five studies of stainless steel welders and the occurrence of lung cancer. Asbestos exposure and smoking habits have been taken into account. The calculated pooled relative risk estimate was 1.94 with a 95% confidence interval of 1.28-2.93. This result suggests a causal relation between exposure to stainless steel welding and lung cancer.

The treated incidence of psychotic and affective illness in twins compared with population expectation: a study in the Swedish Twin and Psychiatric Registries.

Twin studies of psychiatric illness assume that the genetic and environmental risk factors for psychiatric illness are similar in twins and non-twins and in monozygotic (MZ) and dizygotic (DZ) twins. To test this assumption, we examine whether the treated incidence of psychiatric illness in twins deviates from population expectations or differs between MZ and DZ twins. Using first admissions to the Swedish Psychiatric Registry for the years 1979-83 for all twins born 1886-1958 from the Swedish Twin Registries, we calculated Standardized Morbidity Ratios (SMRs) using national incidence rates together with individually computed person-years at risk in the twin cohort. The diagnoses examined, for which there was more than 393000 person-years of risk, were schizophrenia, other non-affective psychoses (ONAP), bipolar affective illness (BPAI), unipolar affective illness (UPAI) and neurotic depression (ND). The SMRs (and 95% Cls) for all twins were: schizophrenia 0.86 (0.69-1.06), ONAP 1.05 (0.88-1.24), BPAI 1.09 (0.90-1.32), UPAI 1.05 (0.85-1.29) and ND 0.99 (0.88-1.10). This pattern of results did not differ substantially when examined separately by gender or birth cohort. Relative risks for first admissions for MZ v. same-sex DZ twins or same v. opposite-sex DZ twins did not differ significantly from unity for any of the disorders examined. In Sweden, the treated incidence of psychotic and affective disorders in twins does not differ from that found in the general population and does not differ across zygosity groups. These results support the validity of the twin method for the study of psychotic and affective disorders.