The Effect of Uncertainty in Exposure Estimation on the Exposure-Response Relation between 1,3-Butadiene and Leukemia

In a follow-up study of mortality among North American synthetic rubber industry workers, cumulative exposure to 1,3-butadiene was positively associated with leukemia. Problems with historical exposure estimation, however, may have distorted the association. To evaluate the impact of potential inaccuracies in exposure estimation, we conducted uncertainty analyses of the relation between cumulative exposure to butadiene and leukemia. We created the 1,000 sets of butadiene estimates using job-exposure matrices consisting of exposure values that corresponded to randomly selected percentiles of the approximate probability distribution of plant-, work area/job group-, and year specific butadiene ppm. We then analyzed the relation between cumulative exposure to butadiene and leukemia for each of the 1,000 sets of butadiene estimates. In the uncertainty analysis, the point estimate of the RR for the first non zero exposure category (>0–<37.5 ppm-years) was most likely to be about 1.5. The rate ratio for the second exposure category (37.5–<184.7 ppm-years) was most likely to range from 1.5 to 1.8. The RR for category 3 of exposure (184.7–<425.0 ppm-years) was most likely between 2.1 and 3.0. The RR for the highest exposure category (425.0+ ppm-years) was likely to be between 2.9 and 3.7. This range off RR point estimates can best be interpreted as a probability distribution that describes our uncertainty in RR point estimates due to uncertainty in exposure estimation. After considering the complete probability distributions of butadiene exposure estimates, the exposure-response association of butadiene and leukemia was maintained. This exercise was a unique example of how uncertainty analyses can be used to investigate and support an observed measure of effect when occupational exposure estimates are employed in the absence of direct exposure measurements

Determinants of low birth weight in urban Pakistan

Objective: To identify determinants of low birth weight (LBW) in Karachi, Pakistan, including environmental exposures and nutritional status of the mother during pregnancy. Design: Cross-sectional study. Participants: Five hundred and forty mother-infant pairs. We interviewed mothers about obstetric history, diet and exposure to Pb. We measured birth weight and blood lead level (BLL). We performed multiple log binomial regression analysis to identify factors related to LBW.Results: Of 540 infants, 100 (18.5%) weighed 208.7 mg/d), infants of mothers with MUAC less than or equal to the median and dietary vitamin C intake \u3e 208-7 mg/d (adjPR = 10.80, 95 % CI 1.46, 79.76), mothers with MUAC above the median and vitamin C intak

Temporal Trends and Factors Associated with Bisphosphonate Discontinuation and Restart

Adverse events related to long-term use of bisphosphonates have raised interest in temporary drug discontinuation. Trends in bisphosphonate discontinuation and restart, as well factors associated with these decisions, are not fully understood at a population level. We investigated temporal trends of bisphosphonate discontinuation from 2010 to 2015 and identified factors associated with discontinuation and restart of osteoporosis therapy. Our cohort consisted of long-term bisphosphonate users identified from 2010 to 2015 Medicare data. We defined discontinuation as 6512\u2009months without bisphosphonate prescription claims. We used conditional logistic regression to compare factors associated with alendronate discontinuation or osteoporosis therapy restart in the 120-day period preceding discontinuation or restart referent to the 120-day preceding control periods. Among 73,800 long-term bisphosphonate users, 59,251 (80.3%) used alendronate, 6806 (9.2%) risedronate, and 7743 (10.5%) zoledronic acid, exclusively. Overall, 26,281 (35.6%) discontinued bisphosphonates for at least 12\u2009months. Discontinuation of bisphosphonates increased from 1.7% in 2010, reaching a peak of 14% in 2012 with levels plateauing through 2015. The factors most strongly associated with discontinuation of alendronate were: benzodiazepine prescription (adjusted odds ratio [aOR] = 2.5; 95% confidence interval [CI] 2.1, 3.0), having a dual-energy X-ray absorptiometry (DXA) scan (aOR = 1.8; 95% CI 1.7, 2.0), and skilled nursing facility care utilization (aOR = 1.8; 95% CI 1.6, 2.1). The factors most strongly associated with restart of osteoporosis therapy were: having a DXA scan (aOR = 9.9; 95% CI 7.7, 12.6), sustaining a fragility fracture (aOR = 2.8; 95% CI 1.8, 4.5), and an osteoporosis or osteopenia diagnosis (aOR = 2.5; 95% CI 2.0, 3.1). Our national evaluation of bisphosphonate discontinuation showed that an increasing proportion of patients on long-term bisphosphonate therapy discontinue medications. The factors associated with discontinuation of alendronate were primarily related to worsening of overall health status, whereas traditional factors associated with worsening bone health were associated with restarting osteoporosis medication. \ua9 2019 American Society for Bone and Mineral Research

Placebo Adherence, Clinical Outcomes, and Mortality in the Womenʼs Health Initiative Randomized Hormone Therapy Trials

Medication adherence may be a proxy for healthy behaviors and other factors that affect outcomes. Prior studies of the association between placebo adherence and health outcomes have been limited primarily to men enrolled in clinical trials and cardiovascular disease outcomes. We examined associations between adherence to placebo and the risk of fracture, coronary heart disease, cancer, and all-cause mortality in the two Women’s Health Initiative (WHI) hormone therapy randomized trials

Prevalence and socio-demographic factors associated with tobacco smoking among adult males in rural Sindh, Pakistan

This cross-sectional study was undertaken to determine the prevalence of tobacco smoking and to obtain information on socio-demographic factors associated with tobacco smoking among adult males in a rural district of Sindh Province, Pakistan. We used a one-stage cluster sampling frame to identify 411 adult males from the study site. We found a high prevalence, 55% of current smokers among this rural population. The median age of initiation of smoking was 20 years. Awareness of the adverse effects of smoking on lung and heart diseases was 86% and 77%, respectively. Smoking prevalence increased with age and income, and was highest among subjects aged 44 years and above (76%) and with incomes of more than PKR 4000 (72%). The high prevalence of smoking suggests that there is an urgent need for developing intervention plans to address this major public health problem in this region

A systematic review of epidemiologic studies of styrene and cancer

<p>Previous epidemiology reviews of exposure to styrene and the risk of cancer considered studies published through 13 November 2013. Since then, additional relevant research has been published. No review has included meta-analyses. The current systematic review considered research published through June 2017; included meta-analyses of the relationship between any exposure to styrene and cancers identified as being of concern, including non-Hodgkin lymphoma (NHL), leukemia and cancers of the esophagus, pancreas, lung and kidney; and evaluated several other forms of cancer. Meta-relative risks for all studies were 1.14 (95% confidence interval (CI), 0.91–1.43) for NHL, 1.00 (95% CI, 0.80–1.26) for multiple myeloma, 0.98 (95% CI, 0.87–1.09) for all leukemia, 1.03 (95% CI, 0.92–1.15) for esophageal cancer, 1.02 (95% CI, 0.93–1.12) for pancreatic cancer, 1.09 (95% CI, 0.95–1.24) for lung cancer and 1.10 (95% CI, 0.99–1.22) for kidney cancer. Individual studies provided little evidence of exposure-response or induction time trends. Limitations of the available research and of the meta-analyses included reliance in most studies on mortality data rather than on incidence data, lack of quantitative estimates of styrene exposure for individual subjects and lack of information on lifestyle factors. Consideration of all pertinent data, including substantial recent research, indicates that the epidemiologic evidence on the potential carcinogenicity of styrene is inconclusive and does not establish that styrene causes any form of cancer in humans.</p