How Does Environmental Temperature Affect Farmworkers' Work Rates in the California Heat Illness Prevention Study?

OBJECTIVE: Estimate the association between environmental temperature (wet bulb globe temperature [WBGT]) and work rate over the course of a workday. METHODS: Repeated-measures regression was used to identify characteristics impacting work rate in a cross-sectional study of Latino farmworkers. Minute-by-minute work rate (measured by accelerometer) and WBGT were averaged over 15-minute intervals. RESULTS: Work rate decreased by 4.34 (95% confidence interval [CI], -7.09 to -1.59) counts per minute per degree Celsius WBGT in the previous 15-minute interval. Cumulative quarter hours worked (2.13; 95% CI, 0.82 to 3.45), age (-3.64; 95% CI, -4.50 to -2.79), and dehydration at the end of workday (51.37; 95% CI, 19.24 to 83.50) were associated with counts per minute as were gender, pay type (piece rate vs hourly) and body mass index ≥25 kg/m 2 . The effects of pay type and body mass index were modified by gender. CONCLUSION: Increased temperature was associated with a decrease in work rate.

Are Cal/OSHA Regulations Protecting Farmworkers in California From Heat-Related Illness?

OBJECTIVE: Determine compliance with and effectiveness of California regulations in reducing farmworkers' heat-related illness (HRI) risk and identify main factors contributing to HRI. METHODS: In a cross-sectional study of Latino farmworkers, core body temperature (CBT), work rate, and environmental temperature (WBGT) were monitored over a work shift by individual ingestible thermistors, accelerometers, and weather stations, respectively. Multiple logistic modeling was used to identify risk factors for elevated CBT. RESULTS: Although farms complied with Cal/OSHA regulations, worker training of HRI prevention and hydration replacement rates were insufficient. In modeling (AOR [95% CI]) male sex (3.74 [1.22 - 11.54]), WBGT (1.22 [1.08 - 1.38]), work rate (1.004 [1.002 - 1.006]), and increased BMI (1.11 [1.10 - 1.29]) were all independently associated with elevated CBT. CONCLUSION: Risk of HRI was exacerbated by work rate and environmental temperature despite farms following Cal/OSHA regulations.

Impacts of weather, work rate, hydration, and clothing in heat-related illness in California farmworkers.

BACKGROUND: The primary aim of this study was to investigate the effects of work rate, hydration status, and clothing on core body temperature (CBT) on California farmworkers. METHODS: Two hundred and eighty-seven farmworkers were recruited in Summer 2015, with 259 participants having sufficient data for analysis. We collected CBT, ambient temperature, work rate, body weight loss, and clothing worn by each participant throughout the work day and demographic data from a questionnaire. RESULTS: Multiple regression with CBT as the outcome was used to determine the adjusted associations between CBT, environmental heat load, and worker characteristics. The multivariate regression model showed statistically significant associations of CBT with work rate (ß = .006, 95% CI [0.004, 0.009]) and wet-bulb globe temperature (ß = .03, 95% CI [0.017, 0.05]). CONCLUSION: Results suggest that among our population workload is the primary modifiable risk factor for heat-related illness. As expected, the ambient temperature was also associated with higher risk.

Physical activity and common tasks of California farm workers: California Heat Illness Prevention Study (CHIPS).

Farm workers are at risk of heat related illness (HRI), but their work rates that contribute to HRI have not been objectively assessed. The CHIPS study collected accelerometer data and characterized the physical activity of major farm tasks. Demographic information, work characteristics, and accelerometer data were collected from 575 farm workers in California. Each participating worker contributed measurements over one work shift. An Actical accelerometer was attached securely to a belt worn at the hip. Data were collected at one-minute intervals throughout the work shift. A total of 13 major work-task categories were defined. The mean physical activity counts per minute (cpm) and percentage of the shift spent at moderate and/or vigorous levels of activity were described for each task. Multiple linear regression models were constructed to determine the worker and environmental characteristics contributing to the physical activity level. Mean levels of physical activity ranged from 700 cpm (workers who carry produce) to a low of 150 cpm "ground pruners" who tend low-level plants, with an overall mean of 345 cpm or "light" activity (2 to ≤3 metabolic equivalents). The environmental temperature was the major factor associated with physical activity. A 10°C increase in the median temperature reduced the mean cpm by 135 (95% CI = 87, 193). Age and the tasks of sorting, ground pruning, and harvesting low-level crops were also negatively and independently associated with mean cpm. Incentivized (piece rate) pay, multi-task work, and irrigator work were positively associated with cpm. An interaction was found between piece rate and sex. Men's activity significantly increased (p < 0.001) by a mean of 95 cpm, (95% CI = 38.3, 150.7) if they were paid by the piece, but there was a non-significant association with women's activity level. Workers conducting multiple tasks, irrigators, men, and those earning incentivized (piece rate) pay had higher adjusted mean physical activity levels and are likely at increased risk of heat-related illness on hot days.

Recruitment, Methods, and Descriptive Results of a Physiologic Assessment of Latino Farmworkers: The California Heat Illness Prevention Study.

OBJECTIVE: The California heat illness prevention study (CHIPS) devised methodology and collected physiological data to assess heat related illness (HRI) risk in Latino farmworkers. METHODS: Bilingual researchers monitored HRI across a workshift, recording core temperature, work rate (metabolic equivalents [METs]), and heart rate at minute intervals. Hydration status was assessed by changes in weight and blood osmolality. Personal data loggers and a weather station measured exposure to heat. Interviewer administered questionnaires were used to collect demographic and occupational information. RESULTS: California farmworkers (n = 588) were assessed. Acceptable quality data was obtained from 80% of participants (core temperature) to 100% of participants (weight change). Workers (8.3%) experienced a core body temperature more than or equal to 38.5 °C and 11.8% experienced dehydration (lost more than 1.5% of body weight). CONCLUSIONS: Methodology is presented for the first comprehensive physiological assessment of HRI risk in California farmworkers.

Particulate matter, endotoxin, and worker respiratory health on large Californian dairies.

OBJECTIVE: To assess respiratory exposures and lung function in a cross-sectional study of California dairy workers. METHODS: Exposure of 205 dairy and 45 control (vegetable processing) workers to particulate matter and endotoxin was monitored. Pre- and postshift spirometry and interviews were conducted. RESULTS: Geometric mean inhalable and PM2.5 concentrations were 812 and 35.3 µg/m3 versus 481.9 and 19.6 µg/m3, respectively, for dairy and control workers. Endotoxin concentrations were 329 EU/m3 or 1122 pmol/m3 and 13.5 EU/m3 or 110 pmol/m3, respectively, for dairy and control workers. In a mixed-effects model, forced vital capacity decreased across a work shift by 24.5 mL (95% confidence interval, -44.7 to -4.3; P = 0.018) with log10 (total endotoxin) and by 22.0 mL (95% confidence interval, -43.2 to -0.08; P = 0.042) per hour worked. CONCLUSIONS: Modern California dairy endotoxin exposures and shift length were associated with a mild acute decrease in forced vital capacity.

Mortality in the California Farmer Health Study cohort.

Western agriculture, in comparison with Midwestern and Eastern, is more diverse, with a drier climate, mild winters, and different exposures. This randomly selected cohort of 1947 Californian farmers confirmed the usual finding: a lower mortality rate than general population (by 50%). A low smoking prevalence and healthy worker effect are likely contributors. Although farmers were more likely to die from injuries and skin cancer, death was less likely from Alzheimer's and cerebrovascular diseases. Within the cohort, disability and persistent wheeze were associated with increased mortality. The 200 deaths were insufficient to determine the significance of rare diseases.

Guideline implementation and patient-tailoring strategies to improve medication adherence for schizophrenia.

OBJECTIVE: To determine the effectiveness of an intervention to promote medication adherence. METHOD: Data were collected for adults with exacerbation of schizophrenia who were treated at one of 6 U.S. Department of Veterans Affairs (VA) Medical Centers (VAMCs) in 3 regional VA networks (Veterans Integrated Service Networks [VISNs]) from March 1999 to October 2000. All 6 VAMCs received a basic guideline implementation strategy for medication management of schizophrenia using usual VA procedures. One VAMC within each VISN was randomly selected to receive an enhanced implementation strategy designed to promote guideline-concordant prescribing by physicians and medication adherence by patients. In the enhanced strategy, a research nurse worked with study participants to identify medication adherence barriers and to develop patient-specific strategies to overcome those barriers. Participants (N = 349) were interviewed at enrollment and 6 months later, using the Structured Clinical Interview for the Positive and Negative Syndrome Scale (PANSS), the Barnes Akathisia Rating Scale, and the Schizophrenia Outcomes Module (SCHIZOM). Medication adherence was measured via subjects' self-report, using the SCHIZOM, and from data abstracted from medical records. RESULTS: Participants were primarily male (94%) and nonwhite (69%, primarily African American) with a mean age of 46 years. Medication adherence at follow-up was modeled using logistic regression, controlling for adherence at baseline, demographic characteristics, PANSS total score, akathisia at baseline, family history of mental illness, and substance abuse. A logistic regression model for adherence at follow-up was significant (likelihood ratio = 52.72, df = 14, p < .0001). Patients enrolled at sites receiving the enhanced intervention were almost twice as likely to be adherent at follow-up. Those who were nonadherent at baseline were significantly less likely to be adherent at follow-up. In addition, adherence at follow-up was significantly greater at 2 of the VA networks as compared to the third network. CONCLUSIONS: These data suggest that a patient-centered strategy to identify and overcome barriers to adherence can improve adherence to antipsychotic medications.

Disparities in use of antipsychotic medications among nursing home residents in Arkansas.

Pilot work was conducted to determine whether there were racial disparities in the use of second-generation antipsychotic medications in a sample of 2,717 residents of nursing homes in Arkansas in 2001. Chi square analysis and a logistic regression model were used to examine the relationship between residents' race and likelihood of receiving a second-generation antipsychotic. Other independent variables included in the model were age, gender, and the location of the nursing home. The results indicated racial disparities in use of second-generation antipsychotics among the nursing home residents, with African-American residents less likely to receive these medications than residents from other racial or ethnic groups.