Lung cancer and occupational exposures other than cotton dust and endotoxin among women textile workers in Shanghai, China.

OBJECTIVES: Numerous epidemiological studies of lung cancer among textile workers worldwide consistently indicate reduced risks related to cotton dust exposure, presumably due to endotoxin contamination. Our objective was to investigate associations with other exposures potentially related to lung cancer, including wool and synthetic fibre dusts, formaldehyde, silica, dyes and metals, that have only been studied to a limited extent in the textile industry. METHODS: We conducted a case-cohort study nested within a cohort of 267,400 women textile workers in Shanghai, China. We compared work assignments and exposure histories of 628 incident lung cancer cases, diagnosed during 1989-1998, with those of a reference subcohort of 3188 workers. We reconstructed exposures with a job-exposure matrix developed specifically for textile factories. Cox proportional hazards modelling was applied to estimate age/smoking-adjusted relative risks (hazard ratios) and risk gradients associated with job assignments and specific agents other than cotton dust and endotoxin. RESULTS: No associations were observed for lung cancer with wool, silk or synthetic fibre dusts, or with most other agents. However, increased risks, although statistically imprecise, were noted for ≥ 10 years' exposures to silica (adjusted HR 3.5, 95% CI 1.0 to 13) and ≥ 10 years' exposures to formaldehyde (adjusted HR 2.1, 95% CI 0.4 to 11). CONCLUSIONS: Exposures to silica and formaldehyde, although not widespread among the cohort, may have increased lung cancer risk. Silica is an established human lung carcinogen, whereas there is only weak prior evidence supporting an association with formaldehyde. Both exposures warrant consideration as potential lung carcinogens in textile manufacturing.

Dust and chemical exposures, and miscarriage risk among women textile workers in Shanghai, China.

INTRODUCTION: To investigate possible associations between miscarriage and occupational exposures in the Shanghai textile industry. METHODS: A retrospective cohort study of miscarriages among 1752 women in the Shanghai textile industry was conducted. Reproductive history was self-reported by women and occupational work histories were collected from factory personnel records. Occupational exposures were assigned by linking work history information to an industry-specific job-exposure matrix informed by factory-specific textile process information and industrial hygiene assessments. Estimates of cotton dust and endotoxin exposure were also assigned. Odds ratios (OR) and 95% CI were estimated by multivariate logistic regression, with adjustment for age at pregnancy, educational level, smoking status of the woman and her spouse, use of alcohol, and woman's year of birth. RESULTS: An elevation in risk of a spontaneously aborted first pregnancy was associated with exposure to synthetic fibres (OR 1.89, 95% CI 1.20 to 3.00) and mixed synthetic and natural fibres (OR 3.31, 95% CI 1.30 to 8.42). No increased risks were observed for women working with solvents, nor were significant associations observed with quantitative cotton dust or endotoxin exposures. Associations were robust and similar when all pregnancies in a woman's reproductive history were considered. CONCLUSIONS: Occupational exposure to synthetic fibres may cause miscarriages, and this possibility should be the subject of further investigation.

Occupational risk factors for pancreatic cancer among female textile workers in Shanghai, China.

OBJECTIVES: To investigate whether occupational exposures to dusts and chemicals in the Shanghai textile industry are associated with risk of pancreatic cancer. METHODS: A case cohort study nested in a cohort of 267,400 female textile workers in Shanghai, China was conducted among 180 incident pancreatic cancer cases and an age stratified randomly selected comparison subcohort (n = 3188). A complete occupational history of work in the textile industry was obtained for each woman, and was linked to a job exposure matrix developed for the textile industry to estimate exposures to specific dusts and chemicals. Cumulative exposures to cotton dust and endotoxin were reconstructed from historical and contemporaneous measurements. RESULTS: After adjusting for smoking status, a trend of decreasing risk of pancreatic cancer was observed for increasing cumulative exposures to cotton dust and endotoxin with a lag of 20 years. The hazard ratios for women cumulatively exposed to >143.4 mg/m3 x years of cotton dust and >3530.6 EU/m3 x years of endotoxin were 0.6 (95% CI 0.3 to 0.9) and 0.5 (95% CI 0.3 to 0.9), respectively, compared to unexposed women. There was little evidence that exposures to other textile dusts and chemicals were associated with risk of pancreatic cancer. CONCLUSIONS: Occupational exposure to cotton dust and endotoxin in the textile industry may have reduced risks of pancreatic cancer in this cohort. These associations should be replicated by others before making a firm conclusion of their possible effects on pancreatic cancer.

Occupational risk factors for nasopharyngeal cancer among female textile workers in Shanghai, China.

AIMS: To investigate whether occupational exposure to dusts and chemicals in the Chinese textile industry are associated with risk of nasopharyngeal cancer. METHODS: Sixty seven nasopharyngeal carcinoma (NPC) cases identified during 1989-98 and a random sample (n = 3188) of women were included in a case cohort study nested in a cohort of 267,400 women textile workers in Shanghai, China. A complete occupational history of work in the textile industry was obtained for each woman. A job exposure matrix developed by experienced industrial hygienists was used to assess exposures to specific dusts and chemicals. RESULTS: Risk of NPC is associated with cumulative exposure to cotton dust. The hazard ratio for women cumulatively exposed to >143.4 mg/m3 x years of cotton dust was 3.6 (95% CI 1.8 to 7.2) compared with unexposed women. Trends of increasing risk were also found with increasing duration of exposure to acids and caustics (p = 0.05), and with years worked in dyeing processes (p = 0.06). Women who worked at least 10 years in dyeing processes had a 3.6-fold excess risk of NPC (95% CI 1.0 to 12.1). CONCLUSIONS: Occupational exposure to cotton dust, acids, and caustics, and work in dyeing and printing jobs in the textile industry may have increased risk of NPC in this cohort.

Oral contraceptives and cervical carcinoma in situ in Chile.

A case-control study of cervical carcinoma in situ was conducted in Santiago, Chile, to determine whether risk of this condition is altered by use of oral contraceptives. Responses to a standardized questionnaire were compared in 133 hospitalized cases and 254 age-matched controls selected from the same screening program through which the cases were detected. After controlling for the possible confounding influence of a variety of indices of sexual behavior, socioeconomic status, and prior cytological smears, no increase in risk was found in women who ever used oral contraceptives. No trend of increasing or decreasing risk was seen in relation to duration of use, up to more than 6 years of exposure, or with the passage of time from either initial or most recent exposure. An observed increase in risk in current users of oral contraceptives was not considered likely to represent a causal relationship.

PIP: A case-control study of cervical carcinoma in situ was conducted in Santiago, Chile, to determine whether risk of this condition is altered by the use of oral contraceptives (OCs). Responses to a standardized questionnaire were compared in 133 hospitalized cases and 254 age-matched controls selected from the same screening program through which the cases were detected. After controlling for the possible confounding influence of a variety of indices of sexual behavior, socioeconomic status, and prior cytological smears, no increase in risk was found in women who had ever used OCs. No trend of increasing or decreasing risk was seen in relation to duration of use, up to more than 6 years of exposure. An observed increase in risk in current OC users was not considered likely to represent a causal relationship.

Fecal bile acids in two Japanese populations with different colon cancer risks.

Some workers have associated fecal bile acids with colon cancer frequency. They suggest that the risk for colon cancer increases with a rise in the level of total and degraded fecal bile acids. The Japanese in Hawaii, who are at high risk for this cancer, had higher concentrations of deoxycholic acid (a degraded bile acid) in their fecal specimens than did the people in Akita, Japan, who are at low risk. However, the findings for the other bile acids were unremarkable or inconsistent. These data were suggestive, but not strongly supportive, of a relationship between fecal bile acid patterns and colon cancer risk.

Contraceptive methods and induced abortions and their association with the risk of colon cancer in Shanghai, China.

267400 female textile workers in Shanghai, who were administered a questionnaire at enrollment into a randomised trial of breast self-examination between October 1989 and October 1991, were followed up until the middle of 2000. Based on the 655 women who developed colon cancer, rate ratios (RRs) were estimated and trends in risk assessed using Cox Proportional Hazards Models. Risk was increased in women who used oral contraceptives for over 3 years (RR=1.56, 95% Confidence Interval (CI) 1.01-2.40). A possible increase in risk was also observed in women who received progestational injections during pregnancy (RR=1.24, 95% CI 0.95-1.62), but not in relation to the use of injectable contraceptives. A possible reduction in risk was associated with tubal ligation (RR=0.86, 95% CI 0.71-1.03) and ever having had an induced abortion (RR=0.84, 95% CI 0.71-1.00). No trends in risk were observed in relation to the duration of hormonal contraceptive use or the number of induced abortions. Additional studies of the possible roles contraceptives may play in the aetiology of colon cancer in women at low risk of this disease are warranted.

Conditional switching: a new variety of regression with many potential environmental applications.

We introduce a new form of regression that has many applications to environmental studies. For a sequence composed of key variates with prototypic value chi, this form differs from the estimation of a location parameter-based curve, mu(chi), a scale parameter-based curve, sigma(chi), or other currently used types of regression. Instead of estimating a curve location, scale, or alpha-quantile parameter, it assumes that there are two or more population subgroups; for example, consisting of unsensitized and sensitized individuals, respectively. Although within each subgroup the relationships mu(chi) or sigma(chi) may or may not be horizontal, these relationships are not deemed to be of primary importance. Instead, the mixing parameter P that indexes the proportions of the two subgroups is treated as being related to the key variate value chi. In the sense that its goal is the estimation of a proportion, the new procedure resembles logit regression. But, in terms of the continuous spectrum of values attained by the response variate, the means used to attain its goal are dissimilar from those of logit regression. Specifically, group membership is not known directly but is determined from a proxy continuous variate whose values overlap between groups. Examples are given with simulated and natural data where this new form of regression is applied. We believe that conditional switching regression is a particularly valuable research tool when chemical level chi of an induced asthma attack or birthweight chi measured in a study of the biomarker cotinine's effect on pregnancy outcomes determines whether an attack or a negative outcome occurs.(ABSTRACT TRUNCATED AT 250 WORDS)

Combined oral contraceptives and risk of cervical carcinoma in situ. WHO Collaborative Study of Neoplasia and Steroid Contraceptives.

BACKGROUND: Although the possible influence of oral contraceptives on risk of cervical carcinoma in situ has been the subject of multiple prior investigations, the results have been inconsistent. METHODS: Data from a multinational, collaborative case-control study were analysed to investigate further this possible relationship. To assess potential screening bias, some statistical analyses were restricted to subgroups of cases with and without symptoms at the time of their diagnosis. RESULTS: Relative risk estimates in relation to various features of oral contraceptive use tended to be highest for asymptomatic disease, lowest for disease presenting with vaginal bleeding, and intermediate for disease presenting with other symptoms, suggesting the presence of a screening bias. In women with vaginal bleeding, who are least likely to have been detected by routine screening, no elevated risk of cervical carcinoma in situ was observed in relation to ever having used combined oral contraceptives, but there was an increased risk in users of over 60 months' duration. An increasing trend in risk with duration of use was most pronounced in these women who first used oral contraceptives in the past 5-10 years; and in women who used oral contraceptives for more than 60 months, risk declined with time since last use. CONCLUSION: These findings could reflect a reversible effect of long-term use of oral contraceptives at an intermediate stage in the carcinogenic process, or a non-causal relationship due to unidentified sources of bias or confounding.

Molybdate-dependent transcription of hyc and nar operons of Escherichia coli requires MoeA protein and ModE-molybdate.

In Escherichia coli, ModE-molybdate, a repressor of modABCD operon (molybdate transport), was previously shown to be an additional transcriptional activator of hyc operon (formate hydrogenlyase) and narGHJI operon (respiratory nitrate reductase). However, in a modE mutant, both operons were expressed at about 50% of the wild-type level in a molybdate-dependent manner. This ModE-independent, molybdate-dependent, expression of hyc, narG and narK operons required MoeA protein. An E. coli modE, moeA double mutant failed to produce formate hydrogenlyase or respiratory nitrate reductase activity irrespective of the growth medium. Tungstate substituted for molybdate in the activation of transcription of hyc and nar operons by ModE could not replace molybdate for MoeA-dependent expression. It is proposed that the MoeA-catalyzed product, an activated form of molybdate, interacts with a transcriptional activator/regulator other than ModE and regulates hyc and nar operons.

Interrelationships among subgroups of serum lipoproteins in normal human subjects.

Analytic ultracentrifugation of serum lipoproteins from 80 men and 54 women aged 27--66 was used to determine if specific segments of the high density (HDL), low density (LDL) and very low density (VLDL) lipoprotein schlieren curves could be defined so as to reveal significant correlations among them. Differences in correlations resulted in division of LDL into three subgroups based on flotation rate S(0)(f) 0--7, 7--12, and 12--20) and division of HDL into two subgroups F(0)(1.20) 0--1.5 and s--9). HDL of F(0)(1.20) 2--9 (designated HDL 2--9) correlated negatively with LDL of S(0)(f) 0--7 (LDL 0--7) for all groups, positively with LDL of S(0)(f) 7--12 except in women aged 27--46, and negatively with VLDL except in men aged 47--66. HDL of F1.20(0) 0--1.5 (HDL0-1.5) correlated positively with LDL 0-7 except in men aged 27--46 and with VLDL in all but older men. Some correlations were reduced to non-significant levels by controlling for LDL (0-7) or VLDL. Correlations of HDL and LDL flotation subgroups yielded no significant net correlation between total HDL and LDL. Total HDL was directly correlated with HDL (2-9) (r greater than 0.97) but not with HDL0-1.5. The foregoing suggests that decreased HDL represents reduced HDL2-9 and may be accompanied by increased LDL0-7 and VLDL. LDL0-7 may represent and "atherogenic" LDL subclass in part responsible for increased coronary risk associated with low HDL.

Linear discriminant function analysis in neuropsychological research: some uses and abuses.

The present paper addressed the continued misinterpretation and misapplication of linear discriminant function analysis in neuropsychological research. Methodological problems concerning the influence of shrinkage and stepwise selection procedures on LDFA are virtually ignored and affect both the classification and inferential application of LDFA. Throughout the paper examples of potential abuses of LDFA were cited and data from a familiar research problem was employed to demonstrate procedures which enable more accurate interpretation of LDFA results. Linear discriminant function analysis and its multivariate equivalents are powerful and flexible tools for exploring group differences provided appropriate applications and interpretations of results are made.

Depot-medroxyprogesterone acetate (DMPA) and risk of invasive adenocarcinomas and adenosquamous carcinomas of the uterine cervix. WHO Collaborative Study of Neoplasia and Steroid Contraceptives.

A hospital-based case-control study was conducted in two hospitals in Bangkok, Thailand, and in one hospital each in Chiang Mai, Thailand, Mexico City, Mexico and Nairobi, Kenya. One purpose of this study was to determine whether the long-acting progestational contraceptive, depot-medroxyprogesterone acetate (DMPA), alters risk of invasive cervical carcinomas with adenomatous histological features. Information on prior use of DMPA, screening for cervical cancer, and the suspected risk factors for this disease was ascertained from interviews of 239 women with adenocarcinomas and 85 women with adenosquamous carcinomas, as well of from a large pool of controls, 2534 of whom were matched to the cases included in this report. For selected subsets of these women, a smoking history was also elicited, blood specimens were collected for measurement of antibodies against herpes simplex and cytomegalovirus, and information on sexual behavior was obtained from interviews of their husbands. The relative risk (and 95% confidence interval) of adenomatous cervical carcinomas in women who ever used DMPA was estimated to be 0.75 (0.51, 1.11). No trends in risk were observed with duration of DMPA use, times since first or last use, or age at first use. The results provide reassurance that use of DMPA for over four years does not enhance risk of adenomatous cervical carcinomas, and risk is not increased after a potential latent period of over 12 years since initial exposure.

Cervical carcinoma in situ and use of depot-medroxyprogesterone acetate (DMPA). WHO Collaborative Study of Neoplasia and Steroid Contraceptives.

The relationship of depot-medroxyprogesterone acetate (D-MPA) use to risk of cervical carcinoma in situ was investigated using data from a large multi-national, hospital-based case-control study. To avoid possible detection bias from Pap smear screening, final analyses were restricted to a subset of cases with symptoms at the time of their diagnosis of cervical carcinoma in situ. Relative to nonusers, the risk was elevated in women who had ever used DMPA and increased with duration of use. Decreasing trends in relative risk with times since first and last uses were observed in long-term users. Results from another portion of this same study did not show a relationship of invasive cervical cancer to DMPA use. These findings suggested that if DMPA increases the risk of cervical carcinoma in situ then either this is a reversible effect, or the cervical lesions induced by DMPA tend not to progress to invasive disease.

Airway management in the obese child.

Airway management in severely obese children requires familiarity with the equipment and techniques used for establishing a patent airway. Normal anatomic landmarks are obscured in these patients, making assessment a challenge. Therapy should be individualized, and because the airway is marginal in many of these patients, small insults, such as respiratory tract infection or loss of muscle tone during sleep, can result in a perilous airway. Pediatric airway charts should be maintained and reviewed frequently in emergency departments and clinics caring for these patients. Currently, the body of literature devoted to airway management in obese children is small. Inconsistencies in parameters make comparison of studies difficult. Continued, consistent reporting of airway-management issues in these patients is needed.

Potency of progestogens used in hormonal therapy: toward understanding differential actions.

Progestogens are widely used in contraception and in hormone therapy. Biochemical and molecular biological evidence suggests that progestogens differ widely in their affinities and transcriptional effects via different steroid receptors, and hence cannot be considered as a single class of compounds. Consistent with these observations, recent clinical evidence suggests that, despite their similar progestogenic actions, these differences underlie different side-effect profiles for cardiovascular disease and susceptibility to infectious diseases. However, choice of progestogen for maximal benefit and minimal side-effects is hampered by insufficient comparative clinical and molecular studies to understand their relative mechanisms of action, as well as their relative potencies for different assays and clinical effects. This review evaluates the usage, meaning and significance of the terms affinity, potency and efficacy in different models systems, with a view to improved understanding of their physiological and pharmacological significance. This article is part of a Special Issue entitled 'Menopause'.

Outcomes after simultaneous pancreas and kidney transplantation and the discriminative ability of the C-peptide measurement pretransplant among type 1 and type 2 diabetes mellitus.

BACKGROUND: Earlier studies reporting outcomes after pancreas transplantation have included a combination of C-peptide cutoffs and clinical criteria to classify type 2 diabetes mellitus (T2DM). However, because the kidney is the major site for C-peptide catabolism, C-peptide is unreliable to discriminate the type of diabetes in patients with kidney disease. METHODS: To improve the discriminative power and better classify the type of diabetes, we used a composite definition to identify T2DM: presence of C-peptide, negative glutamic acid decarboxylase antibody, absence of diabetic ketoacidosis, and use of oral hypoglycemics. Additionally among T2DM patients with end-stage renal disease (ESRD), body mass index of <30 kg/m(2) and use of <1 u/kg of insulin per day were selection criteria for suitablity for simultaneous pancreas and kidney transplantation (SPKT). We compared graft and patient survival between T1DM and T2DM after SPKT. RESULTS: Our study cohort consisted of 80 patients, 10 of whom were assigned as T2DM based on our study criteria. Approximately 15% of patients with T1DM had detectable C-peptide. Cox regression survival analyses found no significant differences in allograft (pancreas and kidney) or patient survival between the 2 groups. The mean creatinine clearance at 1 year estimated by the modification of Diet in Renal Disease (MDRD) equation was not significantly different between the 2 groups. Among those with 1 year of follow-up, all patients with T2DM had glycosylate hemoglobin of <6.0 at 1 year versus 92% of those with T1DM. CONCLUSION: SPKT should be considered in the therapeutic armamentarium for renal replacement in selected patients with T2DM and ESRD. Use of C-peptide measurements for ESRD patients can be misleading as the sole criterion to determine the type of diabetes.