Sleep deficiency and breast cancer risk among postmenopausal women in the California teachers study (CTS).

PURPOSE: There is provocative, yet inconsistent, evidence that sleep deficiency may influence the development of breast cancer. The purpose of this study was to evaluate the risk of breast cancer associated with sleep deficiency among postmenopausal women in the California Teachers Study (CTS). METHODS: We conducted a case-control study of 2,856 invasive breast cancer cases and 38,649 cancer-free controls, nested within the CTS. Self-administered questionnaires were used to ascertain several components of sleep deficiency, including quality, latency, duration, disturbance and use of sleep medications. Additionally, a Global Sleep Index (GSI) was created by summing the individual sleep components and categorizing into quartiles. Multivariable logistic regression analyses were used to estimate odds ratios and 95% confidence intervals (OR, 95% CI). RESULTS: Increased breast cancer risks were associated with sleep deficiency. With the exception of duration, linear increases in risk were associated with all the other individual components of sleep deficiency (p-trend ≤ 0.002). The OR for the highest GSI quartile vs. lowest was 1.24, 95% CI 1.12-1.38; p-trend < 0.001). CONCLUSIONS: Sleep deficiency may be a risk factor for breast cancer. Additional prospective studies and those aimed at elucidating underlying mechanism are warranted.

Improving the knowledge and behavior of workplace chemical exposures in Vietnamese-American nail salon workers: a randomized controlled trial.

OBJECTIVES: We assessed the efficacy of trainings with Vietnamese nail salon owners and workers on knowledge and behaviors that could reduce exposures to toxic chemicals in nail products. METHODS: We trained Vietnamese salon owners in California (n = 77) who then trained their workers (n = 200) on best practices. In a cluster randomized controlled trial, we assessed the efficacy of the training on change in knowledge and self-reported behaviors. Data were collected from 2013 to 2016 and analyzed from 2016 to 2017. RESULTS: Compared to the control group, the intervention group had significantly greater increases in knowledge about: safer nail polishes [odds ratio (OR) 3.7 (95% confidence interval (CI) 1.9, 7.2)]; proper ventilation methods (OR 4.2; 95% CI 2.2, 8.1); recommended glove types (OR 3.4; 95% CI 1.9, 6.3); and recommended product handling and storage (OR 4.1; 95% CI 1.7, 9.9). The intervention also increased best practices: using safer nail polishes (OR 3.6; 95% CI 1.9, 6.8); reading product labels (OR 2.6; 95% CI 1.3, 5.0); and wearing long sleeves (OR 2.4; 95% CI 1.3, 4.2). CONCLUSIONS: The owner-to-worker intervention with culturally and linguistically appropriate training for salon owners who then trained workers was effective in promoting knowledge and self-reported behaviors that can reduce workplace chemical exposures.

Birth characteristics and childhood carcinomas.

BACKGROUND: Carcinomas in children are rare and have not been well studied. METHODS: We conducted a population-based case-control study and examined associations between birth characteristics and childhood carcinomas diagnosed from 28 days to 14 years during 1980-2004 using pooled data from five states (NY, WA, MN, TX, and CA) that linked their birth and cancer registries. The pooled data set contained 57,966 controls and 475 carcinoma cases, including 159 thyroid and 126 malignant melanoma cases. We used unconditional logistic regression to calculate odds ratios (ORs) and 95% confidence intervals (CIs). RESULTS: White compared with 'other' race was positively associated with melanoma (OR=3.22, 95% CI 1.33-8.33). Older maternal age increased the risk for melanoma (OR(per 5-year age increase)=1.20, 95% CI 1.00-1.44), whereas paternal age increased the risk for any carcinoma (OR=1.10(per 5-year age increase), 95% CI 1.01-1.20) and thyroid carcinoma (OR(per 5-year age increase)=1.16, 95% CI 1.01-1.33). Gestational age < 37 vs 37-42 weeks increased the risk for thyroid carcinoma (OR=1.87, 95% CI 1.07-3.27). Plurality, birth weight, and birth order were not significantly associated with childhood carcinomas. CONCLUSION: This exploratory study indicates that some birth characteristics including older parental age and low gestational age may be related to childhood carcinoma aetiology.

Parental educational attainment as an indicator of socioeconomic status and risk of childhood cancers.

BACKGROUND: Little has been reported on socioeconomic (SES) patterns of risk for most forms of childhood cancer. METHODS: Population-based case-control data from epidemiological studies of childhood cancer conducted in five US states were pooled and associations of maternal, paternal and household educational attainment with childhood cancers were analysed. Odds ratios (ORs) and 95% confidence intervals were estimated using logistic regression, controlling for confounders. RESULTS: Although there was no association with parental education for the majority of cancers evaluated, there was an indication of a positive association with lower education for Hodgkin's and Burkitt's lymphoma and Wilm's tumour, with the ORs ranging from 1.5 to >3.0 times that of more educated parents. A possible protective effect was seen for lower parental education and astrocytoma and hepatoblastoma, with ORs reduced by 30 to 40%. CONCLUSIONS: These study results should be viewed as exploratory because of the broad nature of the SES assessment, but they give some indication that childhood cancer studies might benefit from a more thorough assessment of SES.

Birth characteristics and the risk of childhood rhabdomyosarcoma based on histological subtype.

BACKGROUND: Little is known about risk factors for childhood rhabdomyosarcoma (RMS) and the histology-specific details are rare. METHODS: Case-control studies formed by linking cancer and birth registries of California, Minnesota, New York, Texas and Washington, which included 583 RMS cases (363 embryonal and 85 alveolar RMS) and 57 966 randomly selected control subjects, were analysed using logistic regression. The associations of RMS (overall, and based on embryonal or alveolar histology) with birth weight across five 500 g categories (from 2000 to 4500 g) were examined using normal birth weight (2500-3999 g) as a reference. Large (>90th percentile) and small (<10th percentile) size for gestational age were calculated based on birth weight distributions in controls and were similarly examined. RESULTS: High birth weight increased the risk of embryonal RMS and RMS overall. Each 500 g increase in birth weight increased the risk of embryonal RMS (odds ratio (OR)=1.27, 95% confidence interval (CI)=1.14-1.42) and RMS overall (OR=1.18, 95% CI=1.09-1.29). Large size for gestational age also significantly increased the risk of embryonal RMS (OR=1.42, 95% CI=1.03-1.96). CONCLUSIONS: These data suggest a positive association between accelerated in utero growth and embryonal RMS, but not alveolar RMS. These results warrant cautious interpretation owing to the small number of alveolar RMS cases.

Obesity, waist size and prevalence of current asthma in the California Teachers Study cohort.

BACKGROUND: Obesity is a risk factor for asthma, particularly in women, but few cohort studies have evaluated abdominal obesity which reflects metabolic differences in visceral fat known to influence systemic inflammation. A study was undertaken to examine the relationship between the prevalence of asthma and measures of abdominal obesity and adult weight gain in addition to body mass index (BMI) in a large cohort of female teachers. METHODS: Prevalence odds ratios (ORs) for current asthma were calculated using multivariable linear modelling, adjusting for age, smoking and race/ethnicity. RESULTS: Of the 88 304 women in the analyses, 13% (n = 11,500) were obese (BMI > or = 30 kg/m(2)) at baseline; 1334 were extremely obese (BMI > or = 40 kg/m(2)). Compared with those of normal weight, the adjusted OR for adult-onset asthma increased from 1.40 (95% confidence interval (CI) 1.31 to 1.49) for overweight women to 3.30 (95% CI 2.85 to 3.82) for extremely obese women. Large waist circumference (>88 cm) was associated with increased asthma prevalence, even among women with a normal BMI (OR 1.37, 95% CI 1.18 to 1.59). Among obese women the OR for asthma was greater in those who were also abdominally obese than in women whose waist was < or = 88 cm (2.36 vs 1.57). Obese and overweight women were at greater risk of severe asthma episodes, measured by urgent medical visits and hospital admissions. CONCLUSIONS: This study confirms the association between excess weight and asthma severity and prevalence, and showed that a large waist was associated with increased asthma prevalence even among women considered to have normal body weight.

Agricultural pesticide use in California: pesticide prioritization, use densities, and population distributions for a childhood cancer study.

Several studies have suggested an association between childhood cancer and pesticide exposure. California leads the nation in agricultural pesticide use. A mandatory reporting system for all agricultural pesticide use in the state provides information on the active ingredient, amount used, and location. We calculated pesticide use density to quantify agricultural pesticide use in California block groups for a childhood cancer study. Pesticides with similar toxicologic properties (probable carcinogens, possible carcinogens, genotoxic compounds, and developmental or reproductive toxicants) were grouped together for this analysis. To prioritize pesticides, we weighted pesticide use by the carcinogenic and exposure potential of each compound. The top-ranking individual pesticides were propargite, methyl bromide, and trifluralin. We used a geographic information system to calculate pesticide use density in pounds per square mile of total land area for all United States census-block groups in the state. Most block groups (77%) averaged less than 1 pound per square mile of use for 1991-1994 for pesticides classified as probable human carcinogens. However, at the high end of use density (> 90th percentile), there were 493 block groups with more than 569 pounds per square mile. Approximately 170,000 children under 15 years of age were living in these block groups in 1990. The distribution of agricultural pesticide use and number of potentially exposed children suggests that pesticide use density would be of value for a study of childhood cancer.

A case-control pilot study of traffic exposures and early childhood leukemia using a geographic information system.

The scientific debate on risk relationships between proximity to electric and magnetic fields and the development of childhood leukemia has recently focused on the role of other factors that may be strongly correlated with power lines. Proximity to high traffic density, as defined by major roadways or automobile counts, and associated socioeconomic neighborhood characteristics have been suggested as potentially important confounders. For traffic or socioeconomic status (SES) to confound any EMF effect these factors would need to have their own independent impact on leukemia risk. This study was designed to use geographic information system (GIS) technology to empirically examine the relationship between traffic density and socioeconomic indicators to early childhood leukemia in an urban area of California. Ninety cases of childhood leukemia diagnosed under the age of five between 1988 and 1994 among children born in San Diego County were matched by gender and birth date to a total of 349 children also born in the county and not known to have developed any cancer. Case-control differences were assessed via conditional logistic regression. No significant differences were observed for the neighborhood median family income of the birth residences. When comparing neighborhoods with median annual income > or = $56,000 to those with incomes < or = $18,000 the odds ratio was 0.86 (95% confidence interval 0.31, 2.38). Traffic density was measured using a variety of methods, including information on average daily traffic counts and road characteristics. None of the measures of traffic were associated with case status. Neither SES or traffic density near the birth address as assessed with GIS methods are strong enough risk factors for leukemia to be confounders which could totally explain the effect of another variable (such as wire code). Associations with the diagnosis address or with more direct exposure measures may differ from those reported here.

Asthma hospitalization trends in California, 1983-1996.

Annual asthma hospitalization rates were calculated for California's ethnically diverse population from 1983 through 1996. Trends were examined for four race/ethnicity groups: Hispanics, African-Americans, non-Hispanic Caucasians, and Asians/Pacific Islanders. The overall rate decreased by 30% during the time period. African-Americans had the highest rate, more that three times greater than the rate for Caucasians. Among children, the rates for Caucasians decreased by one-third, while rates increased for Hispanics and Asians. The rate for African-American children remained generally constant and was four times higher than the rate for Caucasians. Data from 1996 were assessed for repeat admissions, age and sex differences in rates, costs, and progress toward national goals.

Exposure to environmental and mainstream tobacco smoke and risk of spontaneous abortion.

The authors examined the risk of spontaneous abortion from environmental tobacco smoke (ETS) exposure in a prospective study of over 5,000 women conducted in California during 1990-1991. Among nonsmokers, there was little association by hours of ETS exposure at home or work (adjusted odds ratio (OR) for any exposure = 1.01, 95% confidence interval (CI) 0.80-1.27), or by paternal smoking. However, the risks associated with ETS exposure were increased among nonsmokers who had moderate alcohol or heavy caffeine consumption. A moderate association with maternal smoking was observed (adjusted OR for > or = 5 cigarettes per day = 1.3, 95% CI 0.91-1.9).

Childhood asthma along the United States/Mexico border: hospitalizations and air quality in two California counties.

Since the passage of the North American Free Trade Agreement in 1993, there has been an increasing need to monitor environmental health trends that may be related to the rapid industrialization of the United States/Mexico border. We studied two counties on the California/Baja California border to obtain baseline data on trends in childhood asthma hospitalizations and two pollutants that aggravate asthma, ozone and particulate matter (less than 10 microns in diameter), from 1983 to 1994. Hospital discharge records of children 14 years and younger were analyzed, and rates by county, race, and sex were age-adjusted to the 1990 California population. Data on five ozone and particulate matter indices obtained from the California Environmental Protection Agency were used. Imperial County had the highest childhood asthma hospitalization rates in California for non-Hispanic whites and African-Americans, and the second highest for Hispanics. San Diego County had rates below the state average. Over the time period examined, rates in Imperial County increased 59%, while those in San Diego County decreased 9%. Maximum ozone levels increased 64% in Imperial County but decreased 46% in San Diego County. Particulate matter levels were four times higher in Imperial than in San Diego County. High rates of childhood asthma hospitalizations in Imperial County may be partially related to high levels of poverty and worsening air quality conditions produced by increased burdens on the local airshed. Asthma prevalence surveys and binational time-series analyses examining asthma-pollutant relationships are needed.

Moderate maternal alcohol consumption and risk of spontaneous abortion.

Maternal alcoholism is known to have adverse effects on reproduction and fetal development, but the effects of moderate consumption remain controversial. In a previous case-control study, we found a doubled risk of spontaneous abortion with an average consumption of seven or more drinks per week during the first trimester. To confirm this finding while avoiding potential biases from the case-control design, we examined moderate alcohol consumption in a prospective cohort study of over 5,000 pregnant women. An interview in the first trimester asked about alcohol consumption during the week before interview ("during the first trimester") and before pregnancy. We found an increased risk of spontaneous abortion in women who drank more than three drinks per week during the first trimester, with an adjusted odds ratio (OR) of 2.3 [95% confidence interval (CI) = 1.1-4.5]. The increased risk associated with this moderate alcohol consumption may be higher in first than in second trimester abortions, and it is even higher in the first 10 weeks (OR = 3.8; 95% CI = 1.7-8.7), based on small numbers. Consumption of alcohol before pregnancy was not strongly associated with spontaneous abortion.

Serious mushroom poisonings in California requiring hospital admission, 1990 through 1994.

Hunting and consuming wild mushrooms is an increasingly popular avocation, as well as a means of subsistence for certain groups in the United States. Consuming wild mushrooms is relatively safe for persons with the necessary expert knowledge. Each year, however, tragic deaths or illnesses occur when unsuspecting persons ingest toxic mushrooms. We conjectured that there may be vulnerable subgroups that should be targeted for public service announcements and education about mushrooms. Therefore, we reviewed California's hospital discharge database from 1990 through 1994 to ascertain demographic characteristics and outcomes of "serious" mushroom exposures requiring a hospital admission. Children younger than 5 years have a higher rate of hospital admission for "serious" poisonings. Therefore, parents should be reminded of the need for supervising children in areas with wild mushrooms. We did not find evidence that poisoning rates differed significantly between ethnic or racial groups, but this finding may be limited by a failure of these groups to seek care after becoming ill. We discuss briefly the symptoms and treatment of cases of possibly lethal ingestion of amatoxin-containing species of mushrooms.

Psychologic stress in the workplace and spontaneous abortion.

The relation of work-related psychologic stress to spontaneous abortion was examined in a prospective study of 3,953 pregnant, employed members of a prepaid health plan in California, recruited between 1990 and 1991. Information on occupation, psychologic stress-related factors at work, social support at work, physical exertion at work, life events, pregnancy worries, and potential confounders was obtained by a telephone interview. Psychologic job stress and social support at work were assessed using an abbreviated version of the instrument developed by Karasek and colleagues (Los Angeles: University of Southern California, 1986). Results from the multivariate model indicated that, overall, stressful work was not associated with an increased risk of spontaneous abortion. However, interactions were observed between stressful work and maternal age over 32 years (p = 0.04), cigarette smoking (p = 0.02), and primigravidity (p = 0.06). Relative to the odds ratio for stressful work in young, nonsmoking, multigravid women without a history of two or more spontaneous abortions, the odds ratios for spontaneous abortion given stressful work were higher by 2.45 (95% confidence interval (CI) 1.03-5.81) for older women, 2.96 (95% CI 1.16-7.52) for smokers, and 2.27 (95% CI 0.97-5.27) for primigravid women.