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Objective: - To evaluate exposure-response relationships between 1,3-butadiene and styrene and selected diseases among synthetic rubber polymer workers., Methods: - 21,087 workers (16,579 men; 4508 women) were followed from 1943 through 2009 to determine mortality outcomes. Cox regression models estimated rate ratios (RRs) and 95% confidence intervals (CIs) by quartile of cumulative exposure to butadiene or styrene and exposure-response trends for cancers of the bladder, lung, kidney, esophagus and pancreas, and for all nonmalignant respiratory disease (NMRD), chronic obstructive pulmonary disease (COPD) and pneumonia., Results: - Bladder cancer RRs were 2.13 (95% CI = 1.03 to 4.41) and 1.64 (95% CI = 0.76 to 3.54) in the highest quartiles of cumulative exposure to butadiene and styrene, respectively, and exposure-response trends were positive for both monomers (butadiene, trend p = 0.001; styrene, trend p = 0.004). Further analyses indicated that the exposure-response effect of each monomer on bladder cancer was demonstrated clearly only in the subgroup with high cumulative exposure (at or above the median) to the other monomer. Lung cancer was not associated with either monomer among men. Among women, lung cancer RRs were above 1.0 in each quartile of cumulative exposure to each monomer, but exposure-response was not seen for either monomer. Male workers had COPD RRs slightly above 1.0 in each quartile of cumulative exposure to each monomer, but there was no evidence of exposure-response among the exposed. Monomer exposure was not consistently associated with COPD in women or with the other cancer outcomes., Conclusions: - This study found a positive exposure-response relationship between monomer exposures and bladder cancer. The independent effects of butadiene and styrene on this cancer could not be delineated. In some analyses, monomer exposure was associated with lung cancer in women and with COPD in men, but inconsistent exposure-response trends and divergent results by sex do not support a causal interpretation of the isolated positive associations., (Copyright © 2021 The Authors. Published by Elsevier B.V. All rights reserved.)

Objective: Prostate-specific antigen (PSA) is the best established biomarker of semen exposure. PSA in vaginal fluid returns to pre-exposure concentrations within 24-48 h, but the speed of decay during the first 10 h is unknown. We sought to determine how fast PSA concentrations decline during the first 10 h after exposure to semen., Study Design: Women in the 50 enrolled couples were intravaginally inoculated with 10, 20, 100 and 200 μl of their partner's semen and then collected vaginal swabs immediately after, 30 min, 4 h and 10 h after exposure. Forty-seven sets of samples were tested for PSA. Mixed linear models for repeated measures examined the association between log-transformed PSA values and sampling time and semen exposure volume. Sensitivity analyses excluded data from nonabstainers. Fixed-effect estimates from the statistical models were graphed., Results: PSA values were highest at 200 μl inoculation volumes and at earlier post-exposure time points, then decline steadily. The lowest inoculation volume (10 μl) corresponded to the smallest concentration of PSA throughout the post-inoculation time points. Average PSA levels return to clinically non-detectable levels within 10 h only at the lowest semen exposures. The PSA decay curve assumes a very similar profile across all time points and semen amounts., Conclusions: The PSA decay curve is similar for varying semen exposure volumes, with average PSA concentrations remaining above clinical thresholds 10 h after exposure at all except the very smallest semen exposure levels. PSA is an objective marker of recent exposure to semen, permitting such detection with high accuracy., Implications: This study clarifies how PSA values vary at different semen exposure levels and time points during the first 10 h post-exposure. Future contraceptive studies that use PSA as a semen biomarker will be better informed about PSA concentrations at different sampling times and exposure amounts., (Copyright © 2017 Elsevier Inc. All rights reserved.)

We updated the mortality experience of North American synthetic rubber industry workers to include follow-up from 1944 through 2009, adding 11 years of mortality data to previous investigations. The present analysis used Cox regression to examine the exposure-response relationship between 1,3-butadiene (BD) and styrene (STY) parts per million (ppm)-years and leukemia (N = 114 deaths), non-Hodgkin lymphoma (NHL) (N = 89) and multiple myeloma (MM) (N = 48). A pattern of largely monotonically increasing rate ratios across deciles of BD ppm-years and a positive, statistically significant exposure-response trend were observed for BD ppm-years and leukemia. Using continuous, untransformed BD ppm-years the regression coefficient (β) adjusted only for age was 2.6 × 10(-4) (p < 0.01); the regression coefficient adjusted for age, year of birth, race and plant was 2.9 × 10(-4) (p < 0.01). STY ppm-years also displayed a positive exposure-response association with leukemia. STY and BD were strongly correlated, and the separate effects of these two agents could not be estimated. For NHL, a pattern of approximately monotonically increasing rate ratios across deciles of exposure was seen for STY but not for BD; the test of trend was statistically significant in one of five models that used different STY exposure metrics and adjusted for age and other covariates. BD ppm-years and STY ppm-years were not associated with MM. The present analyses indicated a positive exposure-response relationship between BD cumulative exposure and leukemia. This result along with other research and biological information support an interpretation that BD causes leukemia in humans. STY exposure also was positively associated with leukemia, but its independent effect could not be delineated because of its strong correlation with BD, and there is no external support for a STY-leukemia association. STY, but not BD, was associated positively with NHL. The interpretation of this result is uncertain because the exposure-response data were statistically imprecise and because consistent support for causality from other studies is lacking. The current study provides no support for an association between BD or STY and MM., (Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.)

Objective: To determine the impact of hormonal contraceptive methods on risk of HIV acquisition among HIV-negative women cohabiting with HIV-positive male partners., Study Design: From 1994-2012, HIV discordant couples recruited from a couples' voluntary HIV counseling and testing center in Lusaka, Zambia were followed longitudinally. HIV-negative partners were tested quarterly. This analysis is restricted to couples in which the man was HIV-positive and the woman was HIV-negative at enrollment and the man was not on antiretroviral treatment. Multivariate Cox models evaluated associations between time-varying contraceptive methods and HIV acquisition among women. Sensitivity analyses explored exposure misclassification and time-varying confounder mediation., Results: Among 1393 couples, 252 incident infections occurred in women over 2842 couple-years (8.9 infections per 100 couple-years; 95% CI, 7.8-10.0). Multivariate Cox models indicated that neither injectable [adjusted hazard ratio (aHR)=1.2; 95% CI, 0.8-1.7], oral contraceptive pill (OCP, aHR=1.3; 95% CI, 0.9-1.8), or implant (aHR=1.1; 95% CI, 0.5-2.2) use was significantly associated with HIV acquisition relative to non-hormonal contraception controlling for woman's age, literacy and time-varying measures of genital ulceration/inflammation. This remained true when only looking at the subset of infections acquired from the spouse (82% of infections) and additionally controlling for baseline HIV viral load of the male partner, pregnancy status, and time-varying measures of sperm on a vaginal swab wet prep and self-reported unprotected sex. OCP and injectable users reported more unprotected sex (p<.001), and OCP users were more likely to have sperm on vaginal swab (p=.1) than nonhormonal method users., Conclusions: We found no association between hormonal contraception and HIV acquisition risk in women. Condom use and reinforced condom counseling should always be recommended for HIV discordant couples. HIV testing of sex partners together is critical to establish HIV risk, ascertain couple fertility intentions and counsel appropriately., Implications: These findings add to a controversial literature and uniquely address several common design and analytic challenges faced by previous studies. After controlling for confounders, we found no association between hormonal contraception and HIV acquisition risk in women. We support promoting condoms for HIV prevention and increasing the contraceptive method mix to decrease unintended pregnancy., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Purpose: Interactions between bacterial vaginosis (BV) and inflammatory sexually transmitted infections, such as gonorrhea and chlamydial infection, are not well understood. Furthermore, evidence regarding the sexual transmission of BV is equivocal., Methods: We assessed associations between incident BV and incidences of gonorrhea and/or chlamydial infection ("gonorrhea/chlamydia"), as well as similarities in associations for the two processes, among 645 female patients at a sexually transmitted disease clinic in Alabama followed prospectively for 6 months from 1995 to 1998. We identified predictors of both incident BV and gonorrhea/chlamydia and used bivariate logistic regression to determine whether these predictors differed., Results: Participants completed 3188 monthly, follow-up visits. Several factors associated with incident BV involved sexual intercourse: young age (<16 years) at first intercourse (adjusted odds ratio [aOR], 1.5; 95% confidence interval [CI], 1.1-1.9), recent drug use during sex (aOR, 1.7; 95% CI, 1.2-2.5), prevalent trichomoniasis (aOR, 2.8; 95% CI, 1.7-4.6) and incident syphilis (aOR, 9.7; 95% CI, 1.9-48.4). Few statistical differences between potential factors for BV and gonorrhea/chlamydia emerged. BV appeared to precede the acquisition of gonorrhea/chlamydia (pairwise odds ratio, 1.6; 95% CI, 1.1-2.3), and vice versa (pairwise odds ratio, 2.4; 95% CI, 1.7-3.5)., Conclusions: Findings are consistent with a causal role of sexual behavior in the acquisition of BV and confirm that BV facilitates acquisition of gonorrhea/chlamydia and vice versa independently from other risk factors., (Published by Elsevier Inc.)

Purpose: Differential participation and retention can bias the findings of a follow-up study. This problem was evaluated in a study of barrier contraception among women at high STD risk. The goal of this study was to identify predictors of participation and retention and determine whether they could influence study results., Methods: Six-month follow-up study of women attending STD clinics. Determinants of participation and retention were evaluated using logistic and proportional hazards models., Results: Agreement to participate was associated with young age, black race, low education and income, older age at first intercourse, the number of lifetime partners, and STD history. Early attrition was associated with young age, non-black race, higher income, lack of interest/commitment to using the female condom, high coital frequency, no STD history, not using a birth control method at baseline, and with inconsistent condom use, high coital frequency, and pregnancy during follow up., Conclusions: There was little evidence that differential participation influenced the validity of the study. Differential attrition may have biased behavioral measures of intervention effectiveness, but not necessarily measures of condom use effectiveness.

The development of an encapsulated filtering bleb (Tenon's cyst) complicated 56 of 409 consecutive filtering operations (13.7%) performed during a 40-month period after January 1983. Fifteen eyes (27.8% of encapsulated blebs) required surgical revision. The recognition of bleb encapsulation occurred 20.4 +/- 12.7 days (mean +/- standard deviation) postoperatively. Prolonged duration of beta-adrenergic antagonist therapy was associated with an increased frequency of bleb encapsulation (180.6 +/- 128.5 weeks without encapsulation, 229.0 +/- 129.3 weeks with encapsulation, P less than 0.009). Bleb encapsulation occurred in 42 of 272 eyes with previous argon laser trabeculoplasty, but in only 4 of 85 eyes without any previous anterior segment laser (P less than 0.01). Encapsulated filtering blebs developed in 4 of 12 (33.3%) eyes with congenital glaucoma and 4 of 9 (44.4%) eyes with juvenile glaucoma (P less than 0.0002). The intraocular pressures (IOPs) in the eyes with encapsulated filtering blebs were significantly elevated at 1, 2, and 3 postoperative weeks, and at final follow-up compared with eyes without bleb encapsulation.