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Biomedical subjects

Anders Ahlbom

Publications and source records attributed to Anders Ahlbom.

At least 19 recordsLinked to original sources

Hospitalization for depression is associated with an increased risk for myocardial infarction not explained by lifestyle, lipids, coagulation, and inflammation: the SHEEP Study.

BACKGROUND: Depression is considered a risk factor for coronary heart disease (CHD) in initially CHD-free populations. Subclinical CHD or other somatic causes of depressive symptoms might account for the association, however. METHODS: In this case-control study, patients had had their first acute myocardial infarction (AMI). The study included 1799 cases, aged 45-70 years, and 2339, age-, gender-, and hospital-catchment-area-matched control subjects. We calculated odds ratios (OR) with 95% confidence intervals (CI) by multivariate logistic regressions to assess the AMI risk associated with a hospitalization for depression. RESULTS: Forty-seven cases and 22 control subjects had been hospitalized for depression. After adjustment for matching criteria and socioeconomic status, the OR for AMI was 2.9 (1.8-4.9) for ever hospitalized for depression. Patients hospitalized for depression before or after the median time, 15 years and 2 months, between the first hospitalization for depression and AMI, were at similar risk. Adjustment for lifestyle, lipid profile, coagulation, inflammation, prior cardiovascular events, and comorbidity only partly decreased the observed association. CONCLUSIONS: Depression was associated with increased risk for AMI. Subclinical CHD or other somatic causes are unlikely to account for our findings, which also appear not to be explained by established risk factors for AMI.

Aged↗

Genetic variation in p53 and ATM haplotypes and risk of glioma and meningioma.

BACKGROUND: P53 and ATM are central checkpoint genes involved in the repair of DNA damage after ionising irradiation, which has been associated with risk of brain tumours. Therefore, we tested the hypothesis that polymorphisms and haplotypes in p53 and ATM could be associated with glioma and meningioma risk. MATERIAL AND METHODS: Six hundred and eighty glioma cases (298 glioblastoma (GBM)), 503 meningioma cases, and 1555 controls recruited in the Nordic-UK Interphone study, were analysed in association with three polymorphisms in p53 (rs2287499, rs1042533, rs1625895) and five polymorphisms in ATM ( rs228599, rs3092992, rs664143, rs170548, rs3092993). Haplotypes were constructed using the HAPLOSTAT program. RESULTS: The global statistical test of glioblastoma and p53 haplotypes was p = 0.02. The haplotype analysis on glioblastoma revealed the 1-2-2 haplotype (promotor-codon72-intron 6) had a frequency of 6.1% in cases compared with 9.8% in controls (p = 0.003). The 1-2-1 haplotype was significantly more frequent in GBM cases, 10.2%, than in controls, 7.3% (p = 0.02). The haplotype analysis in ATM revealed an increased frequency of the 1-1-1-2-1 haplotype in meningioma cases (33.8%) compared with controls (30.3%) (p = 0.03). The 2-1-2-1-1 haplotype had a lower frequency in meningioma cases (36.1%) than controls (40.7%) (p = 0.009). CONCLUSIONS: This study found both positive and negative associations of haplotypes in p53 for glioblastoma and ATM for meningioma. This study provides new data that could add to our understanding of brain tumour susceptibility.

Adult↗

The effect of leisure-time physical activity on the risk of acute myocardial infarction depending on body mass index: a population-based case-control study.

BACKGROUND: High body mass index (BMI) and lack of physical activity have been recognized as important risk factors for coronary heart disease. The aim of the present study was to evaluate whether leisure-time physical activity compensates for the increased risk of acute myocardial infarction associated with overweight and obesity. METHODS: Data from the SHEEP (Stockholm Heart Epidemiology Program) study were used. The SHEEP study is a large Swedish population-based case-control study, comprising 1204 male and 550 female cases, and 1538 male and 777 female controls, conducted in Stockholm County, Sweden, during the period 1992-1994. Odds ratios (OR), together with 95 % confidence intervals (95% CI), were calculated using unconditional logistic regression, as estimates of the relative risks. RESULTS: Regular leisure-time physical activity was associated with a decreased risk of myocardial infarction among lean, normal-weight and overweight subjects, but not among obese subjects. Obese (BMI > or = 30) and physically active persons had an almost twofold risk of myocardial infarction, compared with normal-weight and sedentary persons (OR 1.85, 95% CI 1.07-3.18). The results were similar for men and women. CONCLUSION: While regular leisure-time physical activity seems to provide protection against myocardial infarction among lean, normal-weight and overweight subjects, this does not appear to be the case in obese subjects.

Acute Disease↗

Widespread pain following whiplash-associated disorders: incidence, course, and risk factors.

OBJECTIVE: To investigate the incidence and course of widespread pain (WP) subsequent to localized pain in subjects with whiplash-associated disorders (WAD); and to investigate the influence of depressive symptoms, neck pain intensity, number of whiplash-associated symptoms, and number of painful body areas on such conditions. METHODS: From a large prospective cohort of injury claimants who reported WAD after motor vehicle collision (MVC; n = 7462), we identified a subgroup with only localized head/neck/back pain, and who responded to one or more followup questionnaires mailed at 6 weeks and 4, 6, and 12 months after the MVC (n = 266). Pain drawings were distributed at the followup, and we defined WP as having 9 or more painful areas, including posterior neck, at any of these occasions. Depressive symptoms were assessed with the Center for Epidemiological Studies Depression Scale and pain intensity with on a visual analog scale (VAS). RESULTS: The cumulative incidence of WP was 21%, and it occurred early after the injury. Continuous WP over the 12 months was rare. The odds for developing WP were greater in those with depressive symptoms (OR 3.2, 95% CI 1.6-6.3), VAS pain intensity 55-100 (OR 3.2, 95% CI 1.3-8.0), reporting > or = 3 pain-associated symptoms (OR 1.9, 95% CI 0.9-3.8), and those reporting 4 or 5 painful body areas (OR 2.6, 95% CI 1.3-5.4). CONCLUSION: WP occurred early in the course. Even though the cumulative incidence was 21%, continuous WP was rare. Subjects with WAD who report early depressive symptoms and more severe neck injury symptoms are at risk of developing WP after MVC.

Accidents, Traffic↗

Risk of brain tumors associated with exposure to exogenous female sex hormones.

The etiology of brain tumors is largely unknown. Prior observations have implicated gender-specific hormones in the pathogenesis of these tumors. In a population-based case-control study, the authors identified all women aged 20-69 years who had been diagnosed with meningioma or glioma during 2000-2002 in four regions of Sweden. Controls were randomly selected from the study base. Detailed information on hormone usage, including use of hormonal contraceptives, hormonal treatment for gynecologic problems, and hormone replacement therapy, was collected from 178 meningioma cases, 115 glioma cases, and 323 controls. Data were analyzed using unconditional logistic regression, adjusting for age, residential area, education, and parity. An increased relative risk of meningioma was found among postmenopausal women for ever use of hormone replacement therapy, with an odds ratio of 1.7 (95% confidence interval: 1.0, 2.8). Women who had used long-acting hormonal contraceptives (subdermal implants, injections, or hormonal intrauterine devices) had an increased risk of meningioma; the odds ratio for at least 10 years of use was 2.7 (95% confidence interval: 0.9, 7.5). Hormone usage was not associated with glioma risk in this study. The findings suggest that the use of female sex steroids may increase the risk of meningioma.

Adult↗

Mobile phone use and risk of parotid gland tumor.

Handheld mobile phones were introduced in Denmark and Sweden during the late 1980s. This makes the Danish and Swedish populations suitable for a study aimed at testing the hypothesis that long-term mobile phone use increases the risk of parotid gland tumors. In this population-based case-control study, the authors identified all cases aged 20-69 years diagnosed with parotid gland tumor during 2000-2002 in Denmark and certain parts of Sweden. Controls were randomly selected from the study population base. Detailed information about mobile phone use was collected from 60 cases of malignant parotid gland tumors (85% response rate), 112 benign pleomorphic adenomas (88% response rate), and 681 controls (70% response rate). For regular mobile phone use, regardless of duration, the risk estimates for malignant and benign tumors were 0.7 (95% confidence interval: 0.4, 1.3) and 0.9 (95% confidence interval: 0.5, 1.5), respectively. Similar results were found for more than 10 years' duration of mobile phone use. The risk estimate did not increase, regardless of type of phone and amount of use. The authors conclude that the data do not support the hypothesis that mobile phone use is related to an increased risk of parotid gland tumors.

Adult↗

Call-related factors influencing output power from mobile phones.

Mobile phone use is increasing but there is also concern for adverse health effects. Well-designed prospective studies to assess several health outcomes are required. In designing a study of mobile phone use, it is important to assess which factors need to be considered in classifying the exposure to radiofrequency fields (RF). A pilot study was performed in Sweden and in the UK 2002 to 2003 to test the feasibility of recruiting a cohort of mobile phone users from a random population sample and from mobile phone subscription lists for a prospective study. As one part of this pilot study, different factors were evaluated regarding possible influence on the output power of the phones. By local switch logging, information on calls made from predefined subscriptions or dedicated handsets were obtained and the output power of phones during calls made indoors and outdoors, in moving and stationary mode, and in rural as well in urban areas were compared. In this experiment, calls were either 1, 1.5 or 5 min long. The results showed that high mobile phone output power is more frequent in rural areas whereas the other factors (length of call, moving/stationary, indoor/outdoor) were of less importance. Urban and rural area should be considered in an exposure index for classification of the exposure to RF from mobile phones and may be assessed by first base station during mobile phone calls or, if this information is not available, possibly by using home address as a proxy.

Cell Phone↗

Factors influencing neck pain intensity in whiplash-associated disorders.

STUDY DESIGN: Cohort study of subjects with whiplash-associated disorders (WAD). OBJECTIVE: To assess the association between preinjury factors and neck pain intensity within 30 days after a motor vehicle collision. SUMMARY OF BACKGROUND DATA: Neck pain is the main symptom in WAD. There are studies of nonspecific musculoskeletal pain suggesting that pain intensity can be modified by psychologic, personal, or social factors, but, to our knowledge, no studies have investigated the association between such factors and neck pain intensity in WAD. METHODS: The subjects (n = 5970) either filed a claim or were treated for neck pain within 30 days after a collision. Neck pain intensity was measured on the visual analog scale. RESULTS: Fair or poor health before the collision was associated with severe neck pain in females (odds ratio 4.0, 95% confidence interval 1.8-8.9). Other associated factors in females included low education and prior neck pain. Low family income was associated with severe neck pain in males (odds ratio 2.3, 95% confidence interval 1.5-3.4), as was prior headache and being unaware of the head position at the time of collision. CONCLUSION: The results suggest that neck pain intensity in WAD seems to be influenced by several factors other than characteristics related to the injury event itself.

Accidents, Traffic↗

Occupational magnetic field exposure and the risk of acoustic neuroma.

BACKGROUND: Acoustic neuroma is the intracranial tumor subtype showing the highest relative risk in relation to ionizing radiation but other environmental risk factors are largely unknown. This study was performed to investigate the effect of power frequency magnetic fields. METHOD: A total of 793 cases between 1987 and 1999 were identified through the Swedish cancer registry and 101,762 controls were randomly selected from the total population. Information about occupation was obtained from censuses and linked to gender specific job-exposure matrices based on actual measurements of 50 Hz magnetic field exposure. RESULT: We investigated time-weighted average, peak values, and rate of change of magnetic field exposure considering several different time windows in relation to cancer diagnosis. We found no increases in risks regardless of exposure metric or time window of exposure. CONCLUSION: This study is the largest ever on acoustic neuroma and the first study to evaluate this tumor subtype specifically in relation to extremely low frequency magnetic fields. The results do not support the hypothesis that 50 Hz magnetic fields increase the risk of acoustic neuroma.

Case-Control Studies↗

Low physical activity and mortality in women: baseline lifestyle and health as alternative explanations.

AIMS: The aim of this study was to investigate the association between physical activity and mortality in post-menopausal women. In addition, the authors wanted to investigate to what extent this association could be attributed to confounding from other lifestyle factors, and to reverse causation due to a number of common health problems that may inhibit the ability to exercise. METHODS: A total of 27,734 women aged 51-83 years from the Swedish Mammography Cohort were investigated. In 1997 they responded to a detailed questionnaire including questions on physical activity, diet, alcohol intake, smoking, and medical problems. During follow-up in 1999-2004, 1,232 deaths were identified by linkage to the National Population Register. RESULTS: Women with low physical activity (35 MET*h/day) had a 3.22 times increased mortality (95% confidence interval (CI) = 2.35-4.43) compared with the most active women (>50 MET*h/day). No increased risk was seen in women with moderate compared with high physical activity. Sedentary women tended to have a less healthy lifestyle and more health problems at baseline, e.g. almost 30% of them reported high blood pressure compared with less than 20% of active women. Baseline medical problems and lifestyle factors such as smoking, diet, and education accounted for 30% of the excess risk seen in sedentary women (24% and 6% respectively). CONCLUSIONS: This study indicates that even fairly small amounts of activity will reduce mortality in older women. However, sedentary women seemed to be a selected group with more medical problems and a less healthy lifestyle. The findings indicate that the association between physical inactivity and mortality will be overestimated if this is not taken into account.

Aged↗

The magnitude of bias in a cross-sectional study on lifestyle factors in relation to Type 2 diabetes.

AIM: In cross-sectional studies it may be difficult to ascertain the temporal order of exposure and disease, which may have consequences for causal inference. The authors aimed to illustrate the possible magnitude of this potential bias using data from a cross-sectional study on coffee consumption and work stress in relation to type 2 diabetes. METHODS: By a series of computer simulations the authors examined to what extent the observed negative association between type 2 diabetes and high coffee consumption and positive association between type 2 diabetes and high work stress could be due to reverse causality, by assuming that cases changed their exposures in response to development of the disease. RESULTS: If the negative association between coffee and type 2 diabetes was a consequence of reversed causality, 30-40% of the cases would have to decrease their coffee consumption from 5 cups of coffee per day to 3-4 cups per day and from 3-4 cups per day to 2 cups of coffee per day. Moreover, approximately 60% of the cases would have to increase their work stress from low to medium work stress and from medium to high work stress, in order to produce the positive association with diabetes that was observed. CONCLUSION: Even if the type 2 diabetic patients to some extent may have changed their exposure in response to disease development, it seems unlikely that the associations observed between type 2 diabetes, coffee consumption, and work stress are due to this bias.

Adult↗

Genetic effects on physical activity: results from the Swedish Twin Registry.

PURPOSE: The aim of this study was to investigate the genetic effects on leisure-time physical activity using data from the Swedish Twin Registry. METHODS: We investigated 13,362 twin pairs (5334 monozygotic and 8028 dizygotic pairs) aged 14-46 yr. Information on leisure-time physical activity was obtained by questionnaire. Correlations and odds ratios of physical activity were calculated for males, females, and monozygotic and dizygotic twins, respectively. Structural equation modeling was used to estimate the contribution of genetic effects as well as common and nonshared environmental factors on leisure-time physical activity. RESULTS: About one third of the twins reported that they exercised regularly (26% in females and 39% in males). The correlations of physical activity were twice as high in monozygotic compared with dizygotic twins, suggesting the presence of genetic effects. The variation in physical activity due to heritage was 57% (95% confidence interval (CI) = 0.49-0.63) in males and 50% (95% CI = 0.49-0.55) in females. The common environmental influence on physical activity was very small compared with the influence from environmental factors unique to the individual. CONCLUSIONS: Our study establishes heredity as an important component behind individual differences in physical activity in adult men and women. This may be one reason behind difficulties in convincing people to adopt an active lifestyle. Still, this study shows that there is a substantial influence on physical activity from environmental factors unique to the individual.

Adolescent↗

Exposure to loud noise and risk of acoustic neuroma.

Exposure to occupational loud noise has been previously identified as a possible risk factor for acoustic neuroma in only one relatively small (n = 86 cases) case-control study of men. The goal of the present study was to further examine the role of loud noise in acoustic neuroma etiology. In their population-based case-control study of both sexes conducted from 1999 to 2002 in Sweden, the authors compared reports on type and duration of occupational and nonoccupational loud noise exposure of 146 acoustic neuroma cases and 564 controls. Controls were randomly selected from the study base and were frequency matched on age, sex, and residential area. The authors found that individuals reporting loud noise exposure from any source were at increased risk for acoustic neuroma (odds ratio (OR) = 1.55, 95% confidence interval (CI): 1.04, 2.30). Exposure to loud noise from machines, power tools, and/or construction increased the risk for acoustic neuroma (OR = 1.79, 95% CI: 1.11, 2.89), as did exposure to loud music (OR = 2.25, 95% CI: 1.20, 4.23). The odds ratio for a latency period of 13 or more years since the first loud noise exposure from any source was 2.12 (95% CI: 1.40, 3.20). The findings of an increased risk of acoustic neuroma with loud noise exposure support previous research.

Adult↗

Survival after hip fracture.

Although it is known that overall mortality is increased after hip fracture, the influence of hip fracture risk factors on the subsequent mortality and cause of death has not been well studied. The objective of this study was to establish the survival after hip fracture in women and to assess the impact of comorbidity on mortality. We identified a complete population-based set of 2,245 incident hip fracture cases and 4,035 randomly selected population-based controls among women 50-81 years old in Sweden and followed these subjects for an average of 5 years through the Swedish National Inpatient and Cause-of-Death Registers. Information on factors related to hip fracture was obtained through linkage to hospital discharge data and through a mailed questionnaire. We studied excess mortality of hip fracture patients compared to controls using survival curves and proportional hazard regression models. During follow-up, 896 hip fracture patients (40%) and 516 (13%) controls died. The relative risk (RR) of death, adjusted for age and previous hospitalization for serious disease, was 2.3 (95% CI 2.0-2.5). Although the highest mortality risks were in the 1st 6 months post-fracture, RRs for fractures versus controls were increased for at least 6 years. Increased mortality was apparent both in those with evidence of comorbidity and those without. Hip fracture patients have a substantially increased risk of death that persists for at least 6 years post-fracture. The relative excess mortality is independent of comorbidity and known hip fracture risk factors.

Age Distribution↗

Genetic liability to fractures in the elderly.

BACKGROUND: The genetic impact on the causation of osteoporotic fractures is unclear. A large twin study is ideally suited to determine the genetic liability to categories of fracture at various ages. METHODS: A cohort of all 33 432 Swedish twins born from 1896 to 1944 was used to evaluate the genetic liability to fracture occurrence in the elderly. The Swedish Inpatient Registry and computer-assisted telephone interviews enabled us to identify 6021 twins with any fracture, 3599 with an osteoporotic fracture, and 1055 with a hip fracture after the age of 50 years. RESULTS: Genetic variation in liability to fracture differed considerably by type of fracture and age. Less than 20% of the overall age-adjusted fracture variance was explained by genetic variation. The age-adjusted heritability of any osteoporotic fracture was slightly greater (0.27; 95% confidence interval [CI], 0.09-0.28), and for hip fracture alone, it was 0.48 (95% CI, 0.28-0.57). Heritability was not attenuated after further adjustment for several known osteoporotic covariates but was considerably greater for first hip fractures before the age of 69 years (0.68; 95% CI, 0.41-0.78) and between 69 and 79 years (0.47; 95% CI, 0.04-0.62) than for hip fractures after 79 years of age (0.03; 95% CI, 0.00-0.26). CONCLUSIONS: The importance of genetic factors in propensity to fractures depends on fracture site and age. The search for susceptibility genes and environmental factors that may modulate expression of these genes in younger elderly patients with hip fracture, the most devastating osteoporotic fracture, should be encouraged. Prevention of fractures in the oldest elderly should focus on lifestyle interventions.

Age Factors↗

Polymorphisms associated with asthma are inversely related to glioblastoma multiforme.

A reduced risk of primary malignant adult brain tumors is observed among people reporting asthma, hay fever, and other allergic conditions; however, findings may be attributed to prediagnostic effects of tumors or recall bias. To determine whether asthma and allergic condition polymorphisms are inversely related to glioblastoma multiforme (GBM) risk, we conducted a population-based case-control study of 111 GBM patients and 422 controls. We identified five single nucleotide polymorphisms on three genes previously associated with asthma [interleukin (IL)-4RA, IL-13, ADAM33] and one gene associated with inflammation (cyclooxygenase-2). Confirming previous literature, we found that self-reported asthma, eczema, and fever are inversely related to GBM [e.g., asthma odds ratio (OR), 0.64; 95% confidence interval (CI), 0.33-1.25]. In addition, IL-4RA Ser478Pro TC, CC, and IL-4RA Gln551Arg AG, AA are positively associated with GBM (OR, 1.64; 95% CI, 1.05-2.55; 1.61; 95% CI, 1.05-2.47), whereas IL-13 -1,112 CT, TT is negatively associated with GBM (0.56; 95% CI, 0.33-0.96). Each of these polymorphism-GBM associations is in the opposite direction of a corresponding polymorphism-asthma association, consistent with previous findings that self-reported asthmatics and people with allergic conditions are less likely to have GBM than are people who do not report these conditions. Because we used germ line polymorphisms as biomarkers of susceptibility to asthma and allergic conditions, our results cannot be attributed to recall bias or effects of GBM on the immune system. However, our findings are also consistent with associations between IL-4RA, IL-13, and GBM that are independent of their role in allergic conditions.

ADAM Proteins↗

Long-term mobile phone use and brain tumor risk.

Handheld mobile phones were introduced in Sweden during the late 1980s. The purpose of this population-based, case-control study was to test the hypothesis that long-term mobile phone use increases the risk of brain tumors. The authors identified all cases aged 20-69 years who were diagnosed with glioma or meningioma during 2000-2002 in certain parts of Sweden. Randomly selected controls were stratified on age, gender, and residential area. Detailed information about mobile phone use was collected from 371 (74%) glioma and 273 (85%) meningioma cases and 674 (71%) controls. For regular mobile phone use, the odds ratio was 0.8 (95% confidence interval: 0.6, 1.0) for glioma and 0.7 (95% confidence interval: 0.5, 0.9) for meningioma. Similar results were found for more than 10 years' duration of mobile phone use. No risk increase was found for ipsilateral phone use for tumors located in the temporal and parietal lobes. Furthermore, the odds ratio did not increase, regardless of tumor histology, type of phone, and amount of use. This study includes a large number of long-term mobile phone users, and the authors conclude that the data do not support the hypothesis that mobile phone use is related to an increased risk of glioma or meningioma.

Adult↗