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Biomedical subjects

G van Belle

Publications and source records attributed to G van Belle.

At least 19 recordsLinked to original sources
PubMed2005

Intracranial meningioma and ionizing radiation in medical and occupational settings.

In a population-based case-control study of 200 cases and 400 controls in western Washington State, the authors assessed associations between meningioma and ionizing radiation in medical and occupational settings. No significant associations were observed for diagnostic studies or occupational settings, but associations were observed for radiation therapy to head or neck (odds ratio 3.7, 95% CI 1.5 to 9.5), especially for neoplastic conditions. Only four patients (2%) had meningiomas that followed high-dose cranial radiation.

Adolescent↗
PubMed2004

Statin therapy and risk of dementia in the elderly: a community-based prospective cohort study.

OBJECTIVE: To assess the association between statin therapy and risk of Alzheimer disease (AD) in a prospective cohort study with documented statin exposure and incident dementia. METHODS: This is a prospective, cohort study of statin use and incident dementia and probable AD. A cohort of 2,356 cognitively intact persons, aged 65 and older, were randomly selected from a health maintenance organization (HMO), and were assessed biennially for dementia. Statin use was identified using the HMO pharmacy database. A proportional hazards model with statin use as a time-dependent covariate was used to assess the statin-dementia/AD association. RESULTS: Among 312 participants with incident dementia, 168 had probable AD. The unadjusted hazard ratios (HRs) with statin use were 1.33 (95% CI 0.95 to 1.85) for all-cause dementia and 0.90 (CI 0.54 to 1.51) for probable AD. Adjusted corresponding HRs were 1.19 (CI 0.82 to 1.75) and 0.82 (CI 0.46 to 1.46). A subgroup analysis of participants with at least one APOE-epsilon4 allele who entered the study before age 80 produced an adjusted HR of 0.33 (CI 0.10 to 1.04). CONCLUSION: Employing time-dependent proportional hazards modeling, the authors found no significant association between statin use and incident dementia or probable AD. In contrast, when the data were analyzed, inappropriately, as a case-control study, the authors found an OR of 0.55 for probable AD, falsely indicating a protective effect of statins. Study design and analytic methods may explain the discrepancy between the current null findings and earlier findings.

Aged↗
PubMed2003

Prognosis in amyotrophic lateral sclerosis: a population-based study.

BACKGROUND: Accurate information on prognosis of ALS is useful to patients, families, and clinicians. METHODS: In a population-based study of ALS in western Washington, the authors assembled a cohort of 180 patients with incident ALS between 1990 and 1994. Information on potential prognostic factors was collected during an in-person interview. Patients also completed the Medical Outcomes Study Short Form 36 (SF-36). Vital status through December 1999 was known for all patients. RESULTS: Median survival was 32 months from onset of symptoms and 19 months from diagnosis. The 5-year survival after diagnosis was 7%. Older age and female sex were strongly associated with poor survival. In multivariable Cox proportional hazards regression models, factors significantly and independently associated with a worse prognosis included older age, any bulbar features at onset, shorter time from symptom onset to diagnosis, lack of a marital partner, and residence in King County. Recursive partitioning identified age, time from symptom onset to diagnosis, and marital status as the strongest predictors of survival. Good summary scores for physical health on the SF-36, but not for mental health, were significantly associated with longer survival than poor scores. CONCLUSION: These findings are consistent with other population-based studies of ALS and confirm its pernicious nature. Older age, female sex, any bulbar features at onset, short time from symptom onset to diagnosis, lack of a marital partner, and disease severity are key prognostic factors. Serial measurement of severity would likely improve predictions.

Adult↗
PubMed2002

History of head trauma and risk of intracranial meningioma: population-based case-control study.

A population-based case-control study in western Washington state was performed to assess the relation between head trauma and meningioma. Based on 200 case and 400 control subjects, head trauma was associated with an increased risk of meningioma (odds ratio = 1.83; 95% CI = 1.28, 2.62), especially head traumas occurring 10 to 19 years before reference date (odds ratio = 4.33; 95% CI = 2.06, 9.10). A dose-response relationship was present for number, but not severity, of head traumas. Whether the associations observed in this study are causal remains unclear.

Adolescent↗
PubMed2002

Brain SPECT: a controlled, blinded assessment of intra-reader and inter-reader agreement.

A detailed assessment of intra- and inter-reader variation in the interpretation of brain SPECT scans has been performed. A random sample was selected from scans performed at a community/teaching hospital in Seattle. Scans were interpreted independently by three experienced readers who were blinded to all patient information. Forty-eight scans were interpreted twice by each reader, for a total of 288 readings. Readers recorded detailed assessments of individual lesions and overall impressions using a standardized reporting form. Intra-observer agreement as reflected in per cent agreement for severity scores ranged from 65% to 100%. Intra-observer agreement on the 'overall impression' was very good for Alzheimer's pattern (kappa=0.73-1.00), and fair to good for the 'heterogeneous pattern' (kappa=0.30-0.63). Inter-observer agreement, as reflected in per cent agreement, ranged from 29% to 100%. Inter-observer agreement about the 'overall impression' was fair to moderate for Alzheimer's pattern (kappa=0.24-0.54) and was poor for the descriptors 'heterogeneous' and 'normal'. It is concluded that brain SPECT has great potential value in many important conditions. This study demonstrates a need for further work in the areas of pattern definition and reduction of observer variation.

Adult↗
PubMed2001

DNA double-strand breaks in mouse kidney cells with age.

A Biojector device fitted with a CO2 cartridge was used to prepare single cell suspensions from kidneys of 12-month- (middle-aged) and 24-month-old (old) C57B1/6 mice. Microgel electrophoresis of DNA from these cells revealed a modest but significant 7.3% increase (P = 0.04) in DNA double-strand breaks in old mice. This increase is equivalent to the DNA damage induced by 0.1 Gray of X-rays (5 double-strand breaks) in kidney cells of 10-month-old mice, as determined by a standard calibration curve. Greater DNA damage with aging was also positively correlated with higher levels of pathology in the kidneys.

Aging↗
PubMed2001

Dietary soy isoflavone intake in older Japanese American women.

OBJECTIVE: In a sample of older Japanese American women, we aimed to: (1) describe the most commonly consumed soy foods, (2) estimate dietary soy isoflavone intake, (3) describe characteristics associated with dietary soy isoflavone intake, and (4) compare our estimates with previously published estimates in other Japanese samples. DESIGN: A 14-item soy food-frequency questionnaire was administered to older Japanese American women and responses were converted to quantitative estimates of soy isoflavones (genistein plus daidzein). Multiple regression was used to examine characteristics associated with dietary soy isoflavone intake, including self-reported lifestyle and cultural factors and dietary intake of various foods ascertained from a semi-quantitative food-frequency questionnaire. To compare our estimates with other samples, a review of the literature was conducted. SETTING/SUBJECTS: Data are from 274 women aged 65+ years, recruited from a longitudinal cohort study of Japanese Americans in King County, Washington State. RESULTS: The soy foods most commonly consumed were tofu (soybean curd), miso (fermented soybean paste) and aburaage (fried thin soybean curd). The mean intake of dietary soy isoflavones was 10.2 (standard deviation (SD), 12.4) mg day(-1), approximately a quarter to a half that of previously published estimates in Japanese samples. Dietary soy isoflavone intake was positively associated with speaking Japanese, the consumption of traditional Japanese dishes (kamaboko, manju and mochi), low-fat/non-fat milk and yellow/red vegetables, vitamin E supplement use, and walking several blocks each day. Dietary soy isoflavone intake was negatively associated with the consumption of butter. CONCLUSIONS: The estimated dietary soy isoflavone intake in Japanese American women living in King County, Washington State was about a quarter to a half that of women living in Japan. Dietary soy isoflavone intake was associated with speaking Japanese and healthy lifestyle and dietary habits.

Aged↗
PubMed2001

Using census data and birth certificates to reconstruct the early-life socioeconomic environment and the relation to the development of Alzheimer's disease.

The early-life environment and its effect on growth and maturation of children and adolescents are associated with several adult chronic diseases, including Alzheimer's disease. Because it is not feasible to collect information prospectively over the average life span, methods to reconstruct the early-life environment of the aged are necessary to evaluate these associations. In a community-based case-control study conducted in the United States, we collected U.S. census records and birth certificates to reconstruct the early-life socioeconomic environment of each elderly subject. Information was found on 82% of the available Alzheimer's disease cases (239 of 292) and 87% of the available controls (245 of 282). We investigated risk of Alzheimer's disease associated with father's occupation, parental age, household size, sibship size, and birth order. Subjects whose fathers were unskilled manual workers or laborers were at higher risk for Alzheimer's disease (odds ratio = 1.80, 95% confidence interval = 1.19--2.73). The risk of Alzheimer's disease was increased with increasing number of people in the household. We also evaluated whether subjects with the apolipoprotein epsilon 4 allele (APOE epsilon 4), a strong genetic risk factor that is not a necessary cause or a sufficient cause by itself for the development of Alzheimer's disease, were at higher risk than subjects who did not carry this allele. Among subjects with the APOE epsilon 4 allele whose fathers held lower-socioeconomic level occupations, the odds of developing Alzheimer's disease were higher (odds ratio = 2.35, 95% confidence interval = 1.07--5.16) compared with subjects without the allele (odds ratio = 1.40, 95% confidence interval = 0.78--2.52). Subjects carrying the APOE epsilon 4 allele alone have a threefold increased risk of Alzheimer's disease (odds ratio = 3.17, 95% confidence interval = 1.99--5.04). Compared with subjects with neither risk factor, subjects with both the genetic and the environmental risk factors (household size of seven or more and father's occupation being manual) had a relatively high risk of Alzheimer's disease (odds ratio = 14.8, 95% confidence interval = 4.9--46). The data suggest that APOE epsilon 4 may modify the associations between father's occupation, other early-life environmental factors, and development of Alzheimer's disease in late life.

Adolescent↗
PubMed2000

Early-life risk factors and the development of Alzheimer's disease.

OBJECTIVE: To investigate the association of early-life factors with AD. BACKGROUND: The early-life environment and its effect on growth and maturation of children and adolescents are linked to many adult chronic diseases (heart disease, stroke, hypertension, and diabetes mellitus), and these effects are also linked to maternal reproduction. AD may have an early-life link. The areas of the brain that show the earliest signs of AD are the same areas of the brain that take the longest to mature during childhood and adolescence. A poor-quality childhood or adolescent environment could prevent the brain from reaching complete levels of maturation. Lower levels of brain maturation may put people at higher risk for AD. METHODS: In a community-based case-control study (393 cases, 377 controls), we investigated the association of early-life factors and AD. Early-life variables include mother's age at patient's birth, birth order, number of siblings, and area of residence before age 18 years. Patient education level and apolipoprotein E (APOE) genotypes were also included in the analysis. RESULTS: Area of residence before age 18 years and number of siblings are associated with subsequent development of AD. For each additional child in the family the risk of AD increases by 8% (OR = 1.08, 95% CI = 1.01 to 1.15). More controls compared with cases grew up in the suburbs (OR = 0.45, 95% CI = 0.25 to 0.82). APOE epsilon 4 and the patient's education level did not confound or modify the associations. CONCLUSIONS: The early-life childhood and adolescent environment is associated with the risk of AD.

Adolescent↗
PubMed1999

Cross-sectional versus longitudinal estimates of cognitive change in nondemented older people: a CERAD study. Consortium to Establish a Registry for Alzheimer's Disease.

OBJECTIVES: To investigate the effect of increasing age on cognition in nondemented older people. DESIGN: A cross-sectional and longitudinal analysis. PARTICIPANTS: A total of 454 control subjects for Alzheimer's cases from the cohort assembled by the Consortium to Establish a Registry for Alzheimer's Disease (CERAD). MEASUREMENT: The Mini-Mental State Examination (MMSE) to assess cognitive function. RESULTS: Cross-sectional estimates were derived by generalized linear models and longitudinal estimates by generalized estimating equations. The cross-sectional model indicated a small but significant decline in MMSE of -.4 points per 10 years. The longitudinal model indicated a small but significant increase in MMSE of about +.6 points per 10 years. Evidence of an early learning effect and nonrandom dropout exists. CONCLUSIONS: The question of "normal" aging can be approached by considering cross-sectional information and, usually separately, longitudinal information. This study does both using recently developed statistical methods. We conclude that there is a small but significant decline in scores on the MMSE with increasing population age. The effect can be masked in longitudinal cohorts by a learning effect (especially early in follow-up) and other factors associated with repeated testing.

Aged↗
PubMed1998

Risk of amyotrophic lateral sclerosis and history of physical activity: a population-based case-control study.

OBJECTIVE: To assess in greater detail than previous studies the purported association between a history of physical activity and amyotrophic lateral sclerosis (ALS). METHODS: A population-based case-control study was used to identify risk factors for ALS. Case patients were from 3 counties of western Washington State who were newly diagnosed as having ALS by a neurologist. Two control subjects matched with each case patient for sex and age within 5 years were identified by random digit telephone dialing or random selection from Medicare eligibility lists. All subjects underwent an in-person structured interview including detailed information about physical activity before a reference date, which was the month and year the case patient was diagnosed as having ALS. Various measures of physical activity both at work and leisure time were evaluated using conditional logistic regression taking into account the matching for sex and age. RESULTS: One hundred seventy-four case patients and 348 control subjects participated in the study. Physical activity was not significantly different between case patients and controls--whether at work, leisure time or both combined, and whether during a person's lifetime (from 10 years before reference date back to age 15 years) or during specific decades before reference date. An exception was that case patients reported having participated in organized sports in high school slightly more frequently than control subjects (odds ratio, 1.52; 95% confidence interval, 1.03-2.25). CONCLUSION: A history of physical activity has little, if any, effect on the risk of ALS.

Adolescent↗
PubMed1998

Evaluation of a public-private certified nurse-midwife maternity program for indigent women.

OBJECTIVES: This study assessed the impact of a public-private certified nurse-midwife program on prenatal and delivery outcomes among medically indigent women. METHODS: A population-based quasi-experimental design was used to compare 1 intervention county with 2 nonintervention counties. RESULTS: The program significantly reduced the number of women who received no prenatal care and the risk of acquiring less than adequate prenatal care. Reductions in the proportion of infants born premature or with low birth-weights were of borderline significance. The use of induction and/or stimulation of labor was statistically elevated. CONCLUSIONS: These results suggest that the intervention program was instrumental in reducing some, but not all, negative prenatal and delivery outcomes.

Adult↗
PubMed1997

Occupational exposures and amyotrophic lateral sclerosis. A population-based case-control study.

This population-based case-control study was conducted in three countries in western Washington State to evaluate associations between workplace exposures and the risk of amyotrophic lateral sclerosis (ALS). Cases (n = 174) were all newly diagnosed with ALS by neurologists during 1990-1994, and controls (n = 348), who were matched according to age (+/-5 years) and sex, were identified via random-digit dialing or Medicare enrollment files. Four industrial hygienists blindly assessed detailed lifetime job histories for exposures to metals, solvents, and agricultural chemicals. Case-control comparisons were made for jobs held between 15 years of age and 10 years prior to the cases' dates of diagnosis. After adjustment for age and education, ever exposure to agricultural chemicals was associated with ALS (odds ratio (OR) = 2.0, 95% confidence interval (CI) 1.1-3.5); this association was observed separately in men (OR = 2.4, 95% CI 1.2-4.8) but not in women (OR = 0.9, 95% CI 0.2-3.8). Among men, the odds ratio for low exposure to agricultural chemicals (below the median level for exposed controls) relative to no exposure was 1.5 (95% CI 0.4-5.3), and for high exposure, it was 2.8 (95% CI 1.3-6.1) (p for trend = 0.03). Similar analyses based on the panel's assessment of exposures to metals and solvents showed no associations. These findings suggest an association between ALS and agricultural chemicals in men.

Adolescent↗
PubMed1997

Counting plaques and tangles in Alzheimer's disease: concordance of technicians and pathologists.

Our primary aim is to provide a descriptive approach to the analysis of counts of plaques and tangles by different readers. We wanted to find out whether subjects with minimal training can count plaques and tangles in histological specimens of patients with Alzheimer's disease and controls. Two experienced neuropathologists trained three student helpers to recognize plaques and tangles in slides obtained from autopsy material. After training, the students and pathologists examined coded slides from patients with Alzheimer's disease and controls. Some of the slides were repeated to provide an estimate of reliability. Each reader read four fields which were averaged to obtain estimates of plaque and tangle counts. Raters are compared on four aspects of concordance: location, scale, precision and accuracy. Precision and accuracy are combined to provide an estimate of concordance. We conclude that subjects with minimal training can be taught to count plaques and tangles. Concordance with the neuropathologists was somewhat greater for tangles. This paper also provides a methodology for comparing raters.

Aged↗
PubMed1997

Pulmonary function and respiratory symptoms in forest firefighters.

This study evaluated effects on respiratory health of forest firefighters exposed to high concentrations of smoke during their work shift. This is the first study of cross-shift respiratory effects in forest firefighters conducted on the job. Spirometric measurements and self-administered questionnaire data were collected before and after the 1992 firefighting season. Seventy-six (76) subjects were studied for cross-shift and 53 for cross-season analysis. On average, the cross-season data were collected 77.7 days after the last occupational smoke exposure. The cross-shift analysis identified significant mean individual declines in FVC. FEV1, and FEF25 75. The preshift to midshift decreases were 0.089 L, 0.190 L, and 0.439 I/sec. respectively, with preshift to postshift declines of 0.065 L, 0.150 L, and 0.496 L/sec. Mean individual declines for FVC, FEV1 and FEF25 75 of 0.033 L, 0.104 L, and 0.275 I/sec. respectively, also were noted in the cross-season analysis. The FEV1 changed significantly (p < 0.05). The use of wood for indoor heat also was associated with the declines in FEV1. Although annual lung function changes for a small subset (n = 10) indicated reversibility of effect, this study suggests a concern for potential adverse respiratory effects in forest firefighters.

Adult↗
PubMed1997

Surveillance of nasal and bladder cancer to locate sources of exposure to occupational carcinogens.

OBJECTIVE: To locate sources of occupational exposure to nasal and bladder carcinogens for surveillance follow up in British Columbia, Canada. METHODS: Incident cases of nasal cancer (n = 48), bladder cancer (n = 105), and population based controls (n = 159) matched for sex and age, were interviewed about their jobs, exposures, and smoking histories. Odds ratios (ORs) were calculated for 57 occupational groups with stratified exact methods to control for age, sex, and smoking. RESULTS: Occupational groups at increased risk of nasal cancer included: textile workers (six cases, OR 7.6); miners, drillers, and blasters (six cases, OR 3.5); welders (two cases, OR 3.5); pulp and paper workers (three cases, OR 3.1); and plumbers and pipefitters (two cases, OR 3.0). Nasal cancer ORs were not increased in occupations exposed to wood dust, possibly due to low exposures in local wood industries. Strongly increased risks of bladder cancer were found for sheet metal workers (four cases, OR 5.3), miners (19 cases, OR 4.5), gardeners (six cases, OR 3.7), and hairdressers (three cases, OR 3.2). Among occupations originally considered at risk, the following had increased risks of bladder cancer: painters (four cases, OR 2.8); laundry workers (five cases, OR 2.3); chemical and petroleum workers (15 cases, OR 1.8); machinists (eight cases, OR 1.6); and textile workers (three cases, OR 1.5). CONCLUSIONS: Occupational groups with increased risks and three or more cases with similar duties were selected for surveillance follow up. For nasal cancer, these included textile workers (five were garment makers) and pulp and paper workers (three performed maintenance tasks likely to entail stainless steel welding). For bladder cancer, these included miners (12 worked underground), machinists (five worked in traditional machining), hairdressers (three had applied hair dyes), and laundry workers (three were drycleaners).

Aged↗