PubMed Health⌕ Search

Biomedical subjects

D P Sandler

Publications and source records attributed to D P Sandler.

At least 19 recordsLinked to original sources
PubMed2006

Fertility and exposure to solvents among families in the Agricultural Health Study.

BACKGROUND: Several studies have reported associations between solvent exposure and reduced female fertility, but the evidence is inconclusive for male fertility. OBJECTIVES: To investigate the impact of solvent exposure on subfertility among families of male licensed pesticide applicators in the Agricultural Health Study cohort. METHODS: The couples enrolled between 1993 and 1997. Cross-sectional questionnaire information on work tasks was used to assess exposure to solvents. The data were limited to couples (wife aged less than 40 years) with an attempt at pregnancy in the last four years (n = 2112). RESULTS: Twenty eight per cent of the couples were defined as subfertile (not conceiving a pregnancy after at least 12 months of unprotected intercourse, regardless of whether or not a pregnancy ultimately occurred). Adjusted subfertility odds ratios (OR) for exposure to solvents were calculated with logistic regression. Female (OR 1.42, 95% CI 1.15 to 1.75) and male exposure to solvents (OR 1.21 (95% CI 0.93 to 1.57) for monthly exposure and 1.40 (95% CI 0.97 to 2.03) for daily or weekly exposure) were associated with subfertility. In farming, spouses may share or exchange jobs. To account for potential dual exposure, variables for parental exposure (either parent exposed or both parents exposed) were also defined. Both were strongly associated with subfertility (OR 1.62 (95% CI 1.20 to 2.17) and OR 2.10 (95% CI 1.22 to 3.60), respectively). CONCLUSIONS: Solvents may impair fertility of either gender, though the evidence for female effects is stronger than for male effects.

Adult↗
PubMed2006

High pesticide exposure events among farmers and spouses enrolled in the Agricultural Health Study.

We completed a nested case-control analysis of factors associated with reporting a high pesticide exposure event (HPEE) by pesticide applicators and spouses during the five years since enrollment in the Agricultural Health Study (AHS). Cases and controls were identified from the 16,415 private pesticide applicators and 14,045 spouses with completed five-year follow-up interviews as of October 2000. Among the applicators, 306 cases with at least one HPEE in the five years since enrollment and 612 controls, randomly selected from those without a reported HPEE, were identified for analysis. Among the spouses, 63 cases were identified and 126 controls were selected. Risk for a new HPEE was increased among applicators reporting at enrollment ever having an HPEE with an odds ratio (OR) of 3.8 (95% CI: 2.7, 5.3). Compared to applicators who applied pesticides fewer than 5 days per year, the ORs ranged from 1.4 (95% CI: 0.9, 2.2) for 6 to 10 days per year to 2.2 (95% CI: 1.4, 3.6) for more than 20 application days per year. The incidence of HPEE among Iowa applicators was much greater (8.8/1000 applicators) than among North Carolina applicators (2.0/1000). Spouses reported fewer HPEEs compared to applicators (2/1000 spouses). Overall, the observed risk factors for new HPEEs among applicators are similar to risk factors observed in previous cross-sectional analyses of HPEE history. Further, only 13% of applicators and 22% of spouses with symptoms resulting from HPEE sought medical care, suggesting that pesticide poisoning surveillance data may seriously underreport the frequency of such events.

Adolescent↗
PubMed2005

Lead exposure as a risk factor for amyotrophic lateral sclerosis.

BACKGROUND: The etiology of amyotrophic lateral sclerosis (ALS) likely involves an environmental component. We qualitatively assessed literature on ALS and lead exposure. Problems of study design make case reports and studies of lead in blood or tissues difficult to interpret. Most previous case-control studies found an association of ALS with self-reported occupational exposure to lead, with increased risks of 2- to >4-fold. However, these results may have been affected by recall bias. OBJECTIVE: To address inconsistencies among published reports, we used both lead biomarkers and interview data to assess lead exposure, and we evaluated the role of genetic susceptibility to lead. METHODS: We conducted a case-control study in New England in 1993-1996 with 109 ALS cases and 256 population-based controls. We measured blood and bone lead levels, the latter using X-ray fluorescence, and interviewed participants regarding sources of lead exposure. RESULTS: In our study, ALS was associated with self-reported occupational lead exposure, with a dose response for cumulative days of exposure. ALS was also associated with blood and bone lead levels, with a 1.9-fold increase in risk for each mug/dl increment in blood lead and a 2.3- to 3.6-fold increase for each doubling of bone lead. A polymorphism in the delta-aminolevulinic acid dehydratase gene was associated with a 1.9-fold increase in ALS risk. CONCLUSION: These results, together with previous studies, suggest that lead exposure plays a role in the etiology of ALS. An increase in mobilization of lead from bone into blood may play a role in the acute onset of disease.

Amyotrophic Lateral Sclerosis↗
PubMed2004

Pesticide use and menstrual cycle characteristics among premenopausal women in the Agricultural Health Study.

Menstrual cycle characteristics may have implications for women's fecundability and risk of hormonally related diseases. Certain pesticides disrupt the estrous cycle in animals. The authors investigated the cross-sectional association between pesticide use and menstrual function among 3,103 women living on farms in Iowa and North Carolina. Women were aged 21-40 years, premenopausal, not pregnant or breastfeeding, and not taking oral contraceptives. At study enrollment (1993-1997), women completed two self-administered questionnaires on pesticide use and reproductive health. Exposures of interest were lifetime use of any pesticide and hormonally active pesticides. Menstrual cycle characteristics of interest included cycle length, missed periods, and intermenstrual bleeding. The authors used generalized estimating equations to assess the association between pesticide use and menstrual cycle characteristics, controlling for age, body mass index, and current smoking status. Women who used pesticides experienced longer menstrual cycles and increased odds of missed periods (odds ratio = 1.5, 95% confidence interval: 1.2, 1.9) compared with women who never used pesticides. Women who used probable hormonally active pesticides had a 60-100% increased odds of experiencing long cycles, missed periods, and intermenstrual bleeding compared with women who had never used pesticides. Associations remained after control for occupational physical activity.

Adult↗
PubMed2003

Animal production and wheeze in the Agricultural Health Study: interactions with atopy, asthma, and smoking.

BACKGROUND: Exposure to animals, their feeds, and by-products contribute to respiratory symptoms among farmers. AIMS: To investigate the role of animal exposures and wheeze, and to assess whether their impact differs among susceptible subgroups, including atopics, asthmatics, and smokers. METHODS: Using the Agricultural Health Study, a cohort of pesticide applicators in Iowa and North Carolina enrolled in 1994-97, wheeze associated with animal production was evaluated and interactions among susceptible subgroups assessed. Logistic regression models were used to examine risk factors for wheeze in the past year among 20 468 farmers. RESULTS: Individuals raising animals requiring direct contact had the highest odds ratios (OR) for wheeze (OR(dairy) = 1.26; OR(eggs) = 1.70). A significant dose response was observed for both the number of poultry and the number of livestock on the farm. Farmers who performed veterinary procedures on a daily basis had an OR of 1.51. The odds of wheeze associated with poultry production was greater among atopic than non-atopic individuals. Milking cows daily increased the odds of wheeze in all individuals, with the largest association observed among atopic asthmatic individuals. The impact of dairy, poultry, and egg production varied among smoking groups. Past smokers had the highest odds ratios, followed by never smokers, and then current smokers. The OR(eggs) was 2.88 among past smokers but only 1.46 for never smokers. The OR(eggs) for current smokers of 0.80 might reflect self selection of exposure among smokers. CONCLUSIONS: Results are consistent with animal production and respiratory symptoms, and suggest that subgroups may respond differently to exposure.

Adolescent↗
PubMed2003

Risk factors for agricultural injury: a case-control analysis of Iowa farmers in the Agricultural Health Study.

The purpose of this case-control study nested in the Agricultural Health Study was to assess risk factors for agricultural injury among a large group of Iowa farmers. A questionnaire sent to 6,999 farmers identified 431 cases who had a farm work-related injury requiring medical advice/treatment in the previous year and 473 controls who had no injury in the previous year. We assessed several potential risk factors for injury. A multiple logistic regression analysis showed significant associations between farm work-related injury and weekly farming work hours (> or = 50 hours/week) (OR = 1.65; 95% CI = 1.23-2.21), the presence of large livestock (OR = 1.77; 95% CI = 1.24-2.51), education beyond high school (OR = 1.61; 95% CI = 1.21-2.12), regular medication use (OR = 1.44; 95% CI = 1.04-1.96), wearing a hearing aid (OR = 2.36; 95% CI = 1.07-5.20), and younger age. These results confirm the importance of risk factors identified in previous analytic studies and suggest directions for future research in preventive intervention strategies to reduce farm work-related injuries.

Accidents, Occupational↗
PubMed2001

Cancer incidence after childhood nasopharyngeal radium irradiation: a follow-up study in Washington County, Maryland.

A population from a hearing clinic in Washington County, Maryland, in 1943-1960 was followed to assess the risk of developing neoplasms from radium treatment of the nasopharynx for adenoid hypertrophy. Of the 2,925 subjects who attended the clinic, 904 received radium treatment. A nonconcurrent prospective study compared the cancer incidence among the irradiated persons with that among persons with other treatments. Seven brain tumor cases (three malignant and four benign) were identified in the irradiated group versus none in the nonirradiated group (relative risk = 14.8, 95% confidence interval: 0.76, 286.3). A nonsignificant excess risk of thyroid cancer was detected in the irradiated group based on two cases in the exposed group and one case in the nonexposed group (relative risk = 4.2, 95% confidence interval: 0.38, 46.6). Decreased risks of breast cancer, female genital cancers, and prostate cancer were observed among the irradiated individuals, although these deficits were not statistically significant individually. The decreased risk of sex hormone-related cancers in the irradiated group suggests possible radiation damage to the pituitary, with consequent reduction in pituitary hormone output and alterations in sexual and other hormonal development in early life. This hypothesis needs further evaluation.

Adenoids↗
PubMed2001

Reproducibility of reported farming activities and pesticide use among breast cancer cases and controls. A comparison of two modes of data collection.

PURPOSE: Farming is associated with exposure to many potential hazards including pesticides and other agents, but the quality of self-reported data on farm exposures has not been well studied. METHODS: The reproducibility of self-reported farming history was evaluated among women in a population-based, case-control study of breast cancer in North Carolina. Thirty cases and 31 controls were randomly re-interviewed by telephone an average of 13.8 months after the initial interview. The initial interview was based on a farm-by-farm questionnaire, while the repeat interview was based on a shorter ever/never questionnaire. Agreement was estimated using proportions in exact agreement, kappa (kappa), and intraclass correlation coefficients (ICC). RESULTS: In general, group prevalences and means were higher on re-interview. Kappa estimates ranged from 0.15 to 0.84 among cases, and 0.26 to 0.87 among controls, with most estimates falling between 0.5 and 0.8. Moderate to almost perfect agreement (kappa) was observed for questions on crop work (0.47-0.70), crop type (0.56-0.82), pesticide application to tobacco (0.77), and farm residence (0.84). ICC estimates for continuous variables showed fair to substantial agreement (0.30 to 0.69 among cases, 0.38 to 0.69 among controls). Older cases, less educated cases, cases who lived on more than one farm, and cases with longer time intervals between interviews gave lower total agreement than similar groups of controls. CONCLUSIONS: Agreement estimates in this study are similar to those for other types of exposure information typically collected in epidemiologic studies. Nevertheless, a farm-by-farm method of exposure assessment may be preferable to an ever/never determination.

Agriculture↗
PubMed2001

Studying the epidemiology of attention-deficit hyperactivity disorder: screening method and pilot results.

OBJECTIVE: As part of a larger epidemiologic study of risk factors for attention-deficit hyperactivity disorder (ADHD), this pilot study combined parent and teacher information to estimate ADHD prevalence among elementary school children in a North Carolina county. The methods developed for this study and the pitfalls we encountered illustrate the challenges involved in conducting population-based studies of ADHD. METHODS: We employed 2-stage screening using DSM-IV criteria. Teachers completed behaviour-rating scales for all children. We then administered a structured telephone interview to parents of potential cases. We screened 362 of 424 (85%) children in grades 1 to 5 in 4 schools. RESULTS: According to parent reports, 43 children (12%) had previously been diagnosed with ADHD by a health professional. Thirty-four children (9%) were taking ADHD medication. Forty-six children (12.7%) met study case criteria for ADHD, based on combined teacher and parent reports. Of the 46 cases, 18 (39%) had not been previously identified. Eight previously diagnosed children, however, did not meet case criteria. After we adjusted for nonresponse, the estimated prevalence was 16% (95%CI, 12% to 20%). CONCLUSIONS: These data suggest that the DSM-IV prevalence of ADHD has been substantially underestimated, although the true prevalence in this population may be less than the 16% estimated here. Population-based studies of ADHD are feasible and may provide important information about practice and treatment patterns in community settings, as well as a broader understanding of the etiology and life course of this common disorder.

Attention Deficit Disorder with Hyperactivity↗
PubMed2001

Recruiting a community sample in collaboration with farmworkers.

Few studies have examined health effects of pesticides in farmworkers, possibly because researchers perceive this population to be relatively inaccessible. We conducted an epidemiologic study of health effects among farmworkers in two towns in central Florida--Apopka and Pierson. Apopka is a suburb of Orlando with a diffuse farmworker community working in many crops, whereas Pierson is a small rural town with a tightly knit farmworker community working mainly in ferns. We collaborated with the Farmworker Association of Florida, a grassroots organization representing 6,700 farmworker families. We identified potential participants using membership lists of the Community Trust Federal Credit Union. Members of the Farmworker Association served as recruiters for the study, locating randomly selected Credit Union members and administering a screening interview to determine eligibility. In Apopka 90% of contacted workers were screened, and 79% of eligible workers participated in the study; corresponding proportions in Pierson were 94 and 85%. Farmworkers who had worked for 6-15 years and those who worked in a defined type of agriculture (nursery, citrus, or ferns) were more likely to enroll than others. Thus, while the response rate was good for a multistage recruiting process, study participants had a slightly different work history from those who chose not to enroll. We conclude that it is possible to conduct a study of health outcomes in farmworkers with a defined population and good response rates. Collaboration with the community is essential to the success of such a project, and community characteristics can affect response rates.

Adult↗
PubMed2000

Age at menopause and childbearing patterns in relation to mortality.

Several studies have reported increased mortality risk with early natural menopause. More recently, mortality risk was reported to be reduced among women who gave birth at age > or =40 years. The association between reproductive history and mortality was explored among 826 women in a prospective study involving 18,959 person-years of follow-up (from age 50 to 1990-1991) and 108 deaths. After adjustment for age and other covariates, the risk ratio among parous women was 1.53 (95% confidence interval: 0.58, 4.07) for natural menopause at age < or =45 years compared with > or =51 years. In contrast to a previous report, however, the highest estimated mortality risk was seen among women who gave birth in their forties (adjusted risk ratio = 2.14, 95% confidence interval: 1.05, 4.38) compared with having a last birth at ages 30-34 years.

Adolescent↗
PubMed2000

Retinal degeneration in licensed pesticide applicators.

BACKGROUND: Retinal degeneration is the leading cause of visual impairment in older adults, but little is known about its relationship to neurotoxic exposures. METHODS: The Agricultural Health Study is a cohort study of licensed pesticide applicators from Iowa and North Carolina. We used cross-sectional data from self-administered questionnaires given at enrollment in 1994-1996 to compare pesticide use in 154 applicators who reported retinal degeneration and 17,804 controls. RESULTS: Retinal degeneration was associated with fungicide use (odds ratio = 1.8, 95% confidence interval = 1.3-2.6). This relationship was seen in subgroups defined by state, demographic characteristics, or medical history, as well as in the entire group. Risk increased with cumulative days of fungicide use (P for trend = 0.011) and was greater when application methods involving greater personal exposure were used. Retinal degeneration was also related to use of organochlorine or carbamate insecticides, but these associations were less consistent. Since nearly all applicators used organophosphate insecticides and herbicides, these exposures could not be effectively evaluated. CONCLUSIONS: These results suggest that exposure to some fungicides and insecticides may increase risk of retinal degeneration.

Adolescent↗
PubMed2000

A model for predicting the frequency of high pesticide exposure events in the Agricultural Health Study.

The frequency of self-reported high pesticide exposure events (HPEE) has been recorded in the NCI/EPA/NIEHS Agricultural Health Study (AHS). Fourteen percent (14%) of the enrolled applicators responding reported "an incident or experience while using any pesticide which caused an unusually high exposure." These data show, as expected, that the probability of a report of an HPEE increases with the cumulative number of days of pesticide application reported by the applicator. We have developed a three-parameter model that predicts the risk odds ratio (OR) of an HPEE as a function of the number of days that pesticides are applied. These events are costly in terms of resulting health-care visits, lost time from work, and potential risk for cancer and other chronic diseases. We propose that failure to carefully follow all the pesticide manufacturer's label requirements, inexperience, and random events (i.e., breaking hose) are the three factors responsible for the events observed. Special precautions for new or infrequent users of pesticides are indicated.

Agriculture↗
PubMed2000

Menstrual patterns and risk of adult-onset diabetes mellitus.

We examined the association between menstrual patterns and risk of developing adult-onset diabetes in a prospective study of 668 white, college-educated women who completed menstrual diaries throughout their reproductive years. We calculated summary measures of cycle length and variability and bleeding duration for ages < or = 22, 23-27, 28-32, and 33-37 years. The analysis included 35,418 person-years of follow-up and 49 self-reported cases of diabetes (median age at diagnosis, 63 years). There was no association between diabetes risk and age at menarche, mean cycle length, cycle variability, or frequency of long cycles (> 42 days). Longer bleeding periods in the mid- and late reproductive years were somewhat associated with an increased risk of diabetes (adjusted rate ratio 1.4, 95% confidence interval 1.0-1.8 per day increase in bleeding duration for menses during ages 28-32). These results do not support the association of long or irregular menstrual cycles with post-menopausal diabetes incidence, but do suggest a possible association of longer bleeding duration with subsequent onset of diabetes.

Adult↗
PubMed2000

Risk of ovarian cancer in relation to use of phenolphthalein-containing laxatives.

We examined ovarian cancer risk in relation to use of phenolphthalein-containing laxatives in 410 epithelial ovarian cancer cases and 713 controls. Compared to women who never used a laxative, ever use of a phenolphthalein-containing laxative was not associated with an increased risk of ovarian cancer (odds ratio, OR, 1.1, 95% confidence interval, CI, 0.9-1.4). Risk was slightly, but not significantly, higher with more frequent use (OR 1.2 for 75 or more days of use). When women who used non-phenolphthalein containing laxatives was used as the reference group, the associations were slightly, but not significantly larger (OR 1.4 for any use of phenolphthalein-containing laxatives and OR 1.5 for 75 or more days of use)

Adult↗
PubMed2000

A population-based case-control study of farming and breast cancer in North Carolina.

We examined the role of farming and pesticide exposure among 862 cases and 790 controls in a population-based, case-control study of breast cancer conducted in North Carolina between 1993 and 1996. We obtained exposure information through personal interview. Increasing duration of farming was inversely associated with breast cancer risk; odds ratios (95% confidence intervals) were 1.2 (0.8-1.7), 0.8 (0.5-1.2), 0.7 (0.5-1.1), and 0.6 (0.4-0.9) for 1-10, 11-17, 18-23, and >23 years of farming, respectively, relative to nonfarmers. Inverse associations persisted when farming was restricted to calendar time periods of 2,2-bis(p-chlorophenyl)- 1,1,1-trichloroethane (DDT) use or to farming at ages 9-16. Among women who farmed, odds ratios (ORs) were elevated for those who reported being present in fields during or shortly after pesticide application (OR = 1.8, 95% CI = 1.1-2.8) and for those who reported not using protective clothing while applying pesticides (OR = 2.0; 95% CI = 1.0-4.3), but not among those who reported using protective clothing (OR = 0.8; 95% CI = 0.4-1.8). We conclude that residence or work on farms may be associated with a reduced risk of breast cancer. Nevertheless, our results suggest a possible increased risk of breast cancer among a subgroup of farming women who were most likely to be exposed to pesticides.

Adult↗