Comparison of digital and film chest radiography for detection and medical surveillance of silicosis in a setting with a high burden of tuberculosis.

BACKGROUND: Continuing use of analog film and digital chest radiography for screening and surveillance for pneumoconiosis and tuberculosis in lower and middle income countries raises questions of equivalence of disease detection. This study compared analog to digital images for intra-rater agreement across formats and prevalence of changes related to silicosis and tuberculosis among South African gold miners using the International Labour Organization classification system. METHODS: Miners with diverse radiological presentations of silicosis and tuberculosis were recruited. Digital and film chest images on each subject were classified by four expert readers. RESULTS: Readings of film and soft copy digital images showed no significant differences in prevalence of tuberculosis or silicosis, and intra-rater agreement across formats was fair to good. Hard copy images yielded higher prevalences. CONCLUSION: Film and digital soft copy images show consistent prevalence of findings, and generally fair to good intra-rater agreement for findings related to silicosis and tuberculosis.

Differential aging of median and ulnar sensory nerve parameters.

INTRODUCTION: Nerve conduction velocity slows and amplitude declines with aging. METHODS: Median and ulnar sensory nerves were tested at the annual meetings of the American Dental Association. Seven hundred four subjects had at least two observations. The rate of change in the nerve parameters was estimated while controlling for gender, age, change in hand temperature, baseline body mass index (BMI), and change in BMI. RESULTS: Amplitudes of the median sensory nerve action potentials decreased by 0.58 µV per year, whereas conduction velocity decreased at a rate of 0.41 m/s per year. Corresponding values for the ulnar nerve were 0.89 µV and 0.29 m/s per year. The rates of change in amplitudes did not differ, but the median nerve demonstrated a more rapid loss of conduction velocity. CONCLUSIONS: The rate of change for the median conduction velocity was higher than previously reported. The rate of change of median conduction velocity was significantly greater than for the ulnar nerve.

Measurement of asbestos emissions associated with demolition of abandoned residential dwellings.

Many cities are revitalizing their urban cores through the demolition of abandoned residential dwellings (ARDs). However, data regarding the emissions of asbestos during such an operation are sparse. We measured airborne asbestos emissions from emergency demolitions (demolitions on structures deemed too dangerous to enter and remove asbestos) of ARDs in Detroit. High-flow air sampling was conducted during ARD demolitions. Air samples were analyzed using Phased Contrast Microscopy (PCM), and a subset using Transmission Electron Microscopy (TEM). One hundred and one air samples were collected on 25 emergency demolitions. Fifty-four of the 101 PCM samples (53%) exceeded the limit of detection (LOD). However, only 2 of 46 TEM samples (4%) exceeded the LOD for asbestos; these latter samples were from two different demolitions and each contained a single chrysotile asbestos fiber. Using conservative exposure assumptions and commonly-accepted risk estimation formulae, we estimated the lifetime risk of mesothelioma and lung cancer combined to be less than one case per one million people. Emissions of airborne asbestos during emergency (unabated) ARD demolition operations appear to be negligible. As a result, the associated health risk for asbestos-related disease is also negligible. Reconsideration of current regulatory mandates for asbestos abatement in ARDs may be warranted.

Ecstasy use among college undergraduates: gender, race and sexual identity.

We examined a random sample (N=3606) of undergraduates at one large midwestern university and explored correlates of ecstasy use and how use varied by gender, race, and sexual identity. Approximately 10% of the sample used ecstasy in their lifetime; 7% had used within the past year and 3% within the past month. Ecstasy was the second most likely illicit drug to be used, marijuana being the first. Multivariate logistic regression indicated that while men and women were equally likely to have used ecstasy, excessive partying, sexual identity, and grade point average were strongly correlated with ecstasy use. After adjusting for several factors, the number of sexual partners increased the likelihood of ecstasy use, as did self-reported sexual identity; gay, lesbian, and bisexual students were more than two times as likely to have used ecstasy in the past year. Significant relationships existed between ecstasy use and other substance use such as binge drinking, marijuana use, and cigarette smoking. Implications for interventions are discussed.

Mode effects for collecting alcohol and other drug use data: Web and U.S. mail.

OBJECTIVE: The present study examined mode effects for collecting alcohol and other drug use data using a Web-based survey mode and a U.S. mail-based survey mode for comparison. METHOD: A survey regarding alcohol and other drugs was administered to a randomly selected sample of 7,000 undergraduate students attending a large midwestern research university in the spring of 2001. The sample was randomly assigned to either a Web-based survey mode (n = 3,500) or a U.S. mail-based mode (n = 3,500). RESULTS: The Web survey mode of administration resulted in a final sample that more closely matched the target sample in gender mix than did the U.S. mail survey mode. The response rate for the Web survey mode was significantly higher than for the U.S. mail survey mode. Chi-square results indicated there were significant differences in response propensity by several sample characteristics including sex, race, class year and academic credit hours. Multivariate logistic regression results revealed significant racial and gender differences in the response propensity between and withinmodes. After controlling for design discrepancies, there were no significant differences between modes in data quality or substantive responses to substance-use variables. CONCLUSIONS: The findings of the present study provide strong evidence that Web surveys can be used as an effective mode for collecting alcohol and other drug use data among certain populations who have access to the Internet and high rates of use. Web surveys provide promise for enhancing survey research methodology among undergraduate college students.

Factors associated with weaning in the first 3 months postpartum.

OBJECTIVE: To determine the demographic, behavioral, and clinical factors associated with breastfeeding termination in the first 12 weeks postpartum. STUDY DESIGN: This was a prospective cohort study. POPULATION: Breastfeeding women in Michigan and Nebraska were interviewed by telephone at 3, 6, 9, and 12 weeks postpartum or until breastfeeding termination. OUTCOMES MEASURED: We measured associations of demographic, clinical, and breastfeeding variables with weaning during the first 12 weeks postpartum. RESULTS: A total of 946 women participated; 75% breastfed until 12 weeks. Women older than 30 years and women with at least a bachelor's degree were more likely to continue breastfeeding in any given week. Mastitis, breast or nipple pain, bottle use, and milk expression in the first 3 weeks were all associated with termination. Beyond 3 weeks, women who expressed breast milk were 75% less likely to discontinue breastfeeding than women who did not. Women who used a bottle for some feedings during weeks 4 to 12 were 98% less likely to discontinue breastfeeding than women who did not use a bottle. "Not enough milk" was the most common reason given for termination in weeks 1 through 3 (37%) and weeks 4 through 6 (35%); "return to work" was the most common reason given in weeks 7 through 9 (53%) and weeks 10 through 12 (58%). CONCLUSIONS: Younger women and less educated women need additional support in their breastfeeding efforts. Counseling and assistance should be provided to women with pain and mastitis. Exclusive breastfeeding for the first 3 weeks should be recommended. After the first 3 weeks, bottles and manual expression are not associated with weaning and may improve the likelihood of continuing breastfeeding, at least until 12 weeks.

Low-level mercury exposure and peripheral nerve function.

BACKGROUND: Mercury is known to be neurotoxic at high levels. There have been few studies of potential peripheral neurotoxicity among persons with exposure to elemental mercury at or near background levels. OBJECTIVES: The present study sought to examine the association between urinary mercury concentration and peripheral nerve function as assessed by sensory nerve conduction studies in a large group of dental professionals. METHODS: From 1997 through 2006 urine mercury measurements and sensory nerve conduction of the median and ulnar nerves in the dominant hand were performed, and questionnaires were completed, on the same day in a convenience sample of dental professionals who attended annual conventions of the American Dental Association. Linear regression models, including repeated measures models, were used to assess the association of urine mercury with measured nerve function. RESULTS: 3594 observations from 2656 subjects were available for analyses. Urine mercury levels in our study population were higher than, but substantially overlap with, the general population. The only stable significant positive association involved median (not ulnar) sensory peak latency, and only for the model that was based on initial observations and exclusion of subjects with imputed BMI. The present study found no significant association between median or ulnar amplitudes and urine mercury concentration. CONCLUSIONS: At levels of urine mercury that overlap with the general population we found no consistent effect of urine mercury concentration on objectively measured sensory nerve function.

Recall of age of weaning and other breastfeeding variables.

BACKGROUND: Many studies of the impact of breastfeeding on child or maternal health have relied on data reported retrospectively. The goal of this study was to assess recall accuracy among breastfeeding mothers of retrospectively collected data on age of weaning, reasons for cessation, breast pain, lactation mastitis, and pumping. METHODS: Women in Michigan and Nebraska, U.S.A. were interviewed by telephone every 3 weeks during the first 3 months after the birth of their child, and mailed a questionnaire at 6 months. A subset was interviewed again by telephone approximately 1-3.5 years after the birth. The results for the three recall periods, collected 1994-1998, were compared using correlation, linear and Cox regression analysis, and sensitivity and specificity estimates. RESULTS: The 184 participants were aged 18-42, mostly white (95%) and 63% had an older child. The age of weaning tended to be overestimated in interviews 1-3.5 years after birth compared to those within 3 weeks of the event, by approximately one month for 1-3.5 year recall and two weeks for 6-month recall (p < 0.001 in both cases). Recall accuracy of reasons for weaning varied greatly by reason, with mastitis and return to work having the most recall validity. The sensitivity of 1-3.5 year recall of mastitis was 80%, but was only 54% for nipple cracks or sores. CONCLUSION: Breastfeeding duration among short-term breastfeeders tended to be somewhat overestimated when measured at 1-3.5 years post-partum. Reporting of other breastfeeding characteristics had variable reliability. Studies employing retrospective breastfeeding data should consider the possibility of such errors.

Older boyfriends of adolescent girls: the cause or a sign of the problem?

PURPOSE: There were two aims of this study: (a) to determine the causal relationship between adolescent girls' early sexual activity and the presence of an older boyfriend, and (b) theoretically and empirically contextualize the relationship between these two variables within a model of adolescent problem behavior. METHODS: Secondary analysis was conducted with the 670 adolescent girls of Waves I and II of the public use version of the National Longitudinal Study of Adolescent Health. Girls included in the analyses had not already had an older romantic partner in Wave I but did have a romantic partner in the 18 months before Wave II. Four alternative causal models are proposed and tested using structural equation modeling and a nested model comparison analysis strategy. RESULTS: The model with the best fit to the data depicted the presence of an older partner as a mediator of psychosocial risk factors and adolescent problem behaviors (including early sexual activity). Psychosocial characteristics of adolescent girls in Wave I predicted whether they would enter romantic relationships with older boyfriends by Wave II. In turn, though, the presence of an older boyfriend increased problem behavior in Wave II above and beyond the effects of the psychosocial risk factors. CONCLUSIONS: These findings are discussed in terms of the need for a more comprehensive understanding of the unions between adolescent girls and older boyfriends before statutory rape policies are modified.

A modified version of the CAGE as an indicator of alcohol abuse and its consequences among undergraduate drinkers.

In March of 1999, we conducted a cross-sectional, web-based survey using a random sample of 2041 undergraduate students attending a large, public university in the Midwest. The sample was recruited via e-mail and students completed the Web survey from their computer terminals. Toward the goal of establishing the usefulness of the CAGE when screening undergraduates for alcohol misuse, we first examined the proportion of undergraduates with a positive score on a modified version of the CAGE and then determined the correlates of a positive CAGE score (e.g. alcohol consumption, fear of addiction, etc.). We found preliminary evidence that the question "Have you been afraid you might be alcoholic" may be the best identifier, when compared to the modified CAGE, of at-risk students.

Sexual identity and substance use among undergraduate students.

This study examined the association between sexual identity and use of alcohol and other drugs (AOD) among college undergraduate students. A survey regarding AOD use was administered to a random sample of 3607 undergraduate students. The sample included 65 self-identified lesbian or bisexual (LB) women and 54 self-identified gay or bisexual (GB) men. Multivariate logistic regression indicated that while alcohol use did not differ for LB and heterosexual women, LB women were significantly more likely to experience certain AOD-related consequences, smoke cigarettes, and use marijuana, ecstasy, and other drugs. GB men were significantly less likely than heterosexual men to drink heavily but were more likely to use some drugs. These findings provide evidence that sexual identity is an important predictor of AOD use among undergraduate students. These findings support the need for continued research and intervention efforts that target LGB collegians.

Lactation mastitis: occurrence and medical management among 946 breastfeeding women in the United States.

In 1994-1998, the authors followed 946 breastfeeding women from Michigan and Nebraska for the first 3 months postpartum or until they stopped breastfeeding to describe mastitis incidence, mastitis treatment, and any associations between mastitis occurrence and hypothesized host characteristics and behaviors. Participants were interviewed by telephone at 3, 6, 9, and 12 weeks postpartum or until they ceased breastfeeding. A total of 9.5% reported provider-diagnosed lactation mastitis at least once during the 12-week period, with 64% diagnosed via telephone. After adjustment in a logistic regression model, history of mastitis with a previous child (odds ratio (OR) = 4.0, 95% confidence interval (CI): 2.64, 6.11), cracks and nipple sores in the same week as mastitis (OR = 3.4, 95% CI: 2.04, 5.51), using an antifungal nipple cream (presumably for nipple thrush) in the same 3-week interval as mastitis (OR = 3.4, 95% CI: 1.37, 8.54), and (for women with no prior mastitis history) using a manual breast pump (OR = 3.3, 95% CI: 1.92, 5.62) strongly predicted mastitis. Feeding fewer than 10 times per day was protective regardless of whether or not feeding frequency in the same week or the week before mastitis was included in the model (for the same week: 7-9 times: OR = 0.6, 95% CI: 0.41, 1.01; < or =6 times: OR = 0.4, 95% CI: 0.19, 0.82). Duration of feeding was not associated with mastitis risk.