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Biomedical subjects

D Kleinbaum

Publications and source records attributed to D Kleinbaum.

10 recordsLinked to original sources

The BeLPT: algorithms and implications.

BACKGROUND: The beryllium lymphocyte proliferation test (BeLPT) is used to identify persons with beryllium sensitization. The variability of laboratory results and lack of a "gold standard" have led to questions about the test's performance. Fortunately, a recently published study has credibly estimated standard epidemiologic parameters for the BeLPT. METHODS: Information from this recent study was used to assess the performance of two common algorithms for BeLPT testing. Standard epidemiologic parameters were determined for two common algorithms and then compared. RESULTS: One of the two algorithms was more sensitive than the other (86% vs. 66%). The specificity of both algorithms (99.8% or greater) was high. At an estimated 2% prevalence, the positive predictive value of both algorithms for beryllium sensitization remained high (90% or higher). CONCLUSIONS: A priori characterization of the testing algorithm under consideration can enhance public health decision-making.

Algorithms↗

A randomised controlled trial of postural interventions for prevention of musculoskeletal symptoms among computer users.

AIMS: To examine the effect of two workstation and postural interventions on the incidence of musculoskeletal symptoms among computer users. METHODS: Randomised controlled trial of two distinct workstation and postural interventions (an alternate intervention and a conventional intervention) among 376 persons using computer keyboards for more than 15 hours per week. The incidence of neck/shoulder symptoms and hand/arm symptoms during six months of follow up among individuals in the intervention groups was compared to the incidence in computer users who did not receive an intervention (comparison group). For individuals in the intervention groups, study staff adjusted workstations, where possible, and trained individuals to assume the intervention postures. Individuals reported musculoskeletal symptoms in a weekly diary. Participants who reported discomfort intensity of 6 or greater on a 0-10 visual analogue scale or who reported musculoskeletal symptoms requiring use of analgesic medication were considered symptomatic. RESULTS: There were no significant differences in the incidence of musculoskeletal symptoms among the three intervention groups. Twenty two (18.5%) participants in the alternate intervention group, 25 (20.2%) in the conventional intervention group, and 25 (21.7%) in the comparison group developed incident arm or hand symptoms. Thirty eight (33.3%) participants in the alternate intervention group, 36 (31.0%) in the conventional intervention group, and 33 (30.3%) in the comparison group developed incident neck or shoulder symptoms. Compliance with all components of the intervention was attained for only 25-38% of individuals, due mainly to the inflexibility of workstation configurations. CONCLUSIONS: This study provides evidence that two specific workplace postural interventions are unlikely to reduce the risk of upper extremity musculoskeletal symptoms among computer users.

Adolescent↗

Predictors of Chlamydia trachomatis infection among female adolescents: a longitudinal analysis.

Screening guidelines recommend testing all sexually active female adolescents for Chlamydia trachomatis during a pelvic examination at each clinic visit. Such criteria have been based on cross-sectional studies; new evaluations should take into account multiple clinic visits and assess whether criteria are appropriate when a prior test is negative and risk factors are absent. Because repeated observations on an individual may be correlated, the authors used the generalized estimating equation method. Little information exists on subsequent risk of infection; as control programs develop, approaches targeting high-risk populations for recurrent infections are needed. Using data on females aged 15-19 years who visited family planning clinics more than once from 1988 to 1992 (n = 26,921) in Region X (Alaska, Idaho, Oregon, and Washington), the authors constructed a retrospective cohort. Teens with chlamydia at their first visit were at high risk for subsequent infection (odds ratio = 1.6, 95% confidence interval 1.4-1.7). Among teens uninfected at the first visit and without risk factors at the second, prevalence at the second visit was 6%. When intervisit correlations using the generalized estimating equation method were taken into account, predictors of chlamydial infection were consistent with those in previous cross sectional studies cervicitis, friable cervix, and multiple, new, or symptomatic sex partner(s). These findings support screening sexually active female adolescents at each visit, even if prior tests results are available.

Adolescent↗

Relation of lead and social factors to IQ of low-SES children: a partial replication.

An independent replication of a previous study (Schroeder et al., 1985) of the effects of interactive social environmental factors on the relationship of lead and Stanford-Binet IQ was performed on 75 of 80 low-SES black children screened by county health departments in North Carolina. Children's mean blood lead (PbB) level was 20.8 micrograms/dl (range, 6.3 to 47.4). Multivariate regression analyses showed no significant interactions between PbB and age, sex, maternal IQ, Caldwell home environment score, or SES (Hollingshead Two-Factor Index). There was a highly significant negative relationship between both mean and maximum PbB levels with IQ, p less than .002; that is, IQ decreased linearly as PbB increased. The most accurate and precise regression model included lead, maternal IQ, home environment, and gender.

Child↗

5-year follow-up study of children with low-to-moderate lead absorption: electrophysiological evaluation.

Forty-nine children aged 6 to 12 years were evaluated for residual effects of lead exposure using psychometric, electrophysiological, and medical tests 5 years after initial assessment. The original range of blood lead (PbB) levels was 6-59 (mean = 28) micrograms/dl; the current range was 6-30 (mean = 14) micrograms/dl. A linear relationship between PbB and slow brain wave voltage during sensory conditioning was observed at initial evaluation and at 2-year follow-up. No significant relationship between PbB and slow wave voltage during passive conditioning was found at the 5-year follow-up, although a linear increase in slow wave negativity relative to the current PbB level during active conditioning was suggested by exploratory analyses. Another exploratory analysis revealed a significant linear relationship between the original PbB levels and the latency of waves III and V of the brainstem auditory evoked potential. The latency of both waves increased as a function of original PbB. Increased latency of these waves is suggestive of subclinical pathology of the auditory pathway rostral to the cochlear nucleus, although end-organ impairment cannot be ruled out. No threshold for the effect of Pb on auditory function was apparent.

Brain↗

A method for selecting criteria to evaluate medical care.

This study tests a questionnaire method for eliciting process criteria for medical care appraisal. The questionnaire was sent to national samples of family physicians, pediatricians, and pediatricians specializing in infectious diseases asking their opinions about various clinical actions in 125 clinical situations concerning respiratory infection in infants. Five hundred twenty-four (54%) physicians returned completed questionnaires. Questionnaire responses favored the performance of a majority of actions and opposed very few. Opinions concerning individual actions, particularly diagnostic tests and treatments, varied widely depending upon the clinical situation presented. A second questionnaire sent one year later indicated that the opinions expressed in the first questionnaire remained stable over time, especially if the initial opinion favored performance of the action. Comparison of the questionnaire responses and medical records of a group of practitioners demonstrated that only 55% of actions favored in a practitioner's questionnaire appeared in his records. Although the questionnaire method appears to be a feasible, specific, and reliable means of identifying clinical opinion, there remains considerable discordance between opinion as expressed in the questionnaire and recorded clinical practice.

Humans↗

Alcohol consumption as a risk factor for high blood pressure. Munich Blood Pressure Study.

The Munich Blood Pressure Study (MBS), a 1980-81 cross-sectional study (with follow-up) of a random sample of 3198 Munich citizens aged 30-69 years (response rate 69%), revealed hypertensive blood pressure (BP) values in 17.7% of men and 10.7% of women (WHO criteria). One of the main goals of the MBS was to search for social, behavioral, and environmental risk factors for hypertension. The relationship between BP and five possible risk factors--alcohol consumption (g/day), cigarette smoking, oral contraceptive use, years of education, obesity (BMI)--has been examined. The major emphasis of this report is the relationship of alcohol consumption to BP. Multiple linear and logistic regression analyses were run controlling for both age and sex. All second- and third-order interactions between the independent variables were tested during a backward-stepping procedure. Alcohol consumption appeared as a significant main effect in many of the analyses. The coefficient of the alcohol variable ranged from 0.02 to 0.06 for men and women in the separate linear regression analyses for systolic and diastolic BP. Thus, for example, according to the model, the daily consumption of 1 liter of beer (40 g alcohol) may cause an increase in diastolic BP in women of 2.4 mm Hg.

Adult↗