Agricultural Region Of California Research Articles

Proximity to residential and workplace pesticides application and the risk of progression of Parkinson's diseases in Central California

BackgroundPesticide exposure has consistently been associated with Parkinson's disease (PD) onset. Yet, fewer epidemiologic studies have examined whether pesticides influence PD motor and non-motor symptom progression. ObjectivesUsing a geographic information system tool that integrates agricultural pesticide use reports and land use records to derive ambient exposures at residences and workplaces, we assessed associations between specific pesticides previously related to PD onset with PD symptom progression in two PD patient cohorts living in agricultural regions of California. MethodsWe calculated the pounds of pesticide applied agriculturally near each participant's residential or occupational addresses from 1974 to the year of PD diagnosis, using a geographic information system tool that links the California Pesticide Use Reports database to land use data. We examined 53 pesticides selected a priori as they have previously been associated with PD onset. We longitudinally followed two PD patient cohorts (PEG1 N = 242, PEG2 N = 259) for an average of 5.0 years (SD ± 3.5) and 2.7 years (SD ± 1.6) respectively and assessed PD symptoms using the movement disorder specialist-administered Unified Parkinson's disease Rating Scale part III (UPDRS), Mini-Mental State Examination (MMSE), and Geriatric Depression Scale (GDS). Weighted time-to-event regression models were implemented to estimate effects. ResultsTen agricultural pesticides, including copper sulfate (pentahydrate), 2-methyl-4-chlorophenoxyacetic acid (MCPA) dimethylamine salt, tribufos, sodium cacodylate, methamidophos, ethephon, propargite, bromoxynil octanoate, monosodium methanearsonate (MSMA), and dicamba, were associated with faster symptom progression. Among these pesticides, residential or workplace proximity to higher amounts of copper sulfate (pentahydrate) and MCPA (dimethylamine salt) was associated with all three progression endpoints (copper sulfate: HRs = 1.22–1.36, 95 % CIs = 1.03–1.73; MCPA: HRs = 1.27–1.35, 95 % CIs = 1.02–1.70). ConclusionsOur findings suggest that pesticide exposure may not only be relevant for PD onset but also PD progression phenotypes. We have implicated ten specific pesticide active ingredients in faster PD motor and non-motor decline.

Gestational Exposure to Organophosphate Pesticides and Longitudinally Assessed Behaviors Related to Attention-Deficit/Hyperactivity Disorder and Executive Function.

The brain’s prefrontal cortex directs higher-order cognitive and behavioral processes that are important for attention, working memory, and inhibitory control. We investigated whether gestational exposure to organophosphate (OP) pesticides was associated with these abilities in childhood and early adolescence. Between 1999 and 2000, we enrolled pregnant women in a birth cohort drawn from an agricultural region of California. We measured dialkyl phosphate (DAP) metabolites of OP pesticides in maternal pregnancy urine samples (13 and 26 weeks) and estimated associations with behaviors related to attention-deficit/hyperactivity disorder and executive function, assessed longitudinally; 351 families provided neurodevelopmental outcome data at any point when the child was aged 7–12 years. We assessed function across multiple dimensions (e.g., working memory, attention), methods (e.g., behavior reports, child assessment), and reporters (e.g., mothers, teachers, child self-reports). Higher gestational DAP concentrations were consistently associated with behaviors related to attention-deficit/hyperactivity disorder and executive function. For example, a 10-fold increase in gestational DAP concentration was associated with poorer longitudinally assessed Behavior Rating Inventory of Executive Function scores, as reported by mothers (β = 4.0 (95% confidence interval: 2.1, 5.8); a higher score indicates more problems), and Weschler Intelligence Scale for Children—Fourth Edition Working Memory scores (a 3.8-point reduction; β = −3.8 (95% confidence interval: −6.2, −1.3)). Reducing gestational exposure to OP pesticides through public health policy is an important goal.

Prenatal exposure to organophosphate pesticides and longitudinally assessed executive function and attention in childhood and early adolescence

Background: Neurobehavioral functions governed by the prefrontal cortex, including executive function and attention, impact children’s academic and socioeconomic attainment into adulthood. Pesticide exposures may affect these functions. Objective: To investigate whether prenatal exposure to organophosphate (OP) pesticides is associated with children’s executive functioning and attention at ages 7 to 12 years. Methods: We measured dialkyl phosphates (DAPs), metabolites of OP pesticides, in urine samples collected from pregnant women participating in the Center for the Health Assessment of Mothers and Children of Salinas (CHAMACOS), a population-based cohort study conducted in an agricultural region of California. We assessed executive functioning and attention via maternal report on behavior and standardized assessments of children. We estimated associations of prenatal OP exposure with these outcomes, longitudinally assessed at ages 7, 9, 10.5 and 12 years (n=310 to 341, depending on the time point), adjusting for sociodemographic factors, home learning environment, and maternal receptive language skills and depressive symptoms. Results: Higher prenatal total DAP concentrations (geometric mean (SD) = 130.3 (2.7)) were associated with more parent-reported executive function and attention problems and poorer performance on child assessment measures. For example, a 10-fold increase in prenatal DAP concentrations was associated with a 3.7 point (95% CI 1.8, 5.6) increase in Behavior Rating Inventory of Executive Function Global Executive Composite T-scores and a 3.9 point reduction (95% CI: -6.4, -1.3) in Weschler Intelligence Scales for Children-IV Working Memory scores. Associations were driven primarily by dimethyl phosphates, which are considerably higher than diethyl phosphates in CHAMACOS. In addition, DAP-related associations with parent-reported behavior were stronger in boys than in girls. Discussion: OP pesticide metabolite concentrations during pregnancy were associated with poorer executive functioning and attention at school age and into adolescence. Reducing prenatal exposure to OP pesticides through public health interventions and policy is an important goal.

Lithologic and redox controls on hexavalent chromium in vadose zone sediments of California’s Central Valley

In agricultural regions of California where ultramafic sediments containing naturally occurring Cr(III) are present, correlations between Cr(VI) and nitrate in groundwater have been attributed to oxidation of Cr(III) in vadose sediments and mobilization by areal recharge, including irrigation return. However, the distribution of Cr and nitrate through the vadose zone have yet to be evaluated together to investigate the controls on geogenic Cr(VI) occurrence and resulting Cr(VI) production rates and export fluxes to groundwater. To develop a framework for evaluating geogenic Cr(VI) contamination, we analyze vadose zone sediment cores from the southwestern Sacramento Valley of California at high spatial resolution. In the sandy, oxic, ultramafic, Cr-rich Holocene alluvial sediment, Cr(III) is oxidized to Cr(VI), resulting in increasing Cr(VI) concentrations with depth up to 79 μg/kg. Oxidation is likely associated with μ-meter scale co-located Mn(IV)-oxides. Within the fine-grained Pleistocene sediments beneath the historic high water table (5–18 m), Cr(VI) concentrations decrease with depth to <30 μg/kg due to subsequent reduction. Patterns in Cr(VI) concentration parallel nitrate due to the similar depth of production zones, oxidation-reduction potential and geochemical behavior. Field evidence in the shallow profile also supports Cr(VI) production by enhanced Cr(III) dissolution due to nitrification-induced acidification and subsequent oxidation by Mn-oxides. From Cr(VI) and nitrate concentration gradients with depth through the vadose zone (∼20 m), we calculate field-based net production and removal rates, quantify vadose zone storage (156–1168 kg Cr(VI)/km2; 1 × 105–2.6 × 105 kg N/km2), and estimate export fluxes to groundwater (40–1314 kg Cr(VI)/km2/yr; 5–487 kg N/km2/yr). The framework we present for evaluating vadose zone geogenic Cr(VI) contamination highlights the compounding effects that vadose zone lithology and hydrology can have on solute production, accumulation, development of redoxclines, and subsequent distribution of redox sensitive elements in alluvial sediment and groundwater.

Determinants of pesticide concentrations in silicone wristbands worn by Latina adolescent girls in a California farmworker community: The COSECHA youth participatory action study

Personal exposure to pesticides has not been well characterized, especially among adolescents. We used silicone wristbands to assess pesticide exposure in 14 to 16 year old Latina girls (N = 97) living in the agricultural Salinas Valley, California, USA and enrolled in the COSECHA (CHAMACOS of Salinas Examining Chemicals in Homes and Agriculture) Study, a youth participatory action study in an agricultural region of California. We determined pesticide concentrations (ng/g/day) in silicone wristbands worn for one week using gas chromatography electron capture detection and employed gas chromatography mass spectrometry to determine the presence or absence of over 1500 chemicals. Predictors of pesticide detections and concentrations were identified using logistic regression, Wilcoxon rank sum tests, and Tobit regression models. The most frequently detected pesticides in wristbands were fipronil sulfide (87%), cypermethrin (56%), dichlorodiphenyldichloroethylene (DDE) (56%), dacthal (53%), and trans-permethrin (52%). Living within 100 m of active agricultural fields, having carpeting in the home, and having an exterminator treat the home in the past six months were associated with higher odds of detecting certain pesticides. Permethrin concentrations were lower for participants who cleaned their homes daily (GM: 1.9 vs. 6.8 ng/g/day, p = 0.01). In multivariable regression models, participants with doormats in the entryway of their home had lower concentrations (p < 0.05) of cypermethrin (87%), permethrin (99%), fipronil sulfide (69%) and DDE (75%). The results suggest that both nearby agricultural pesticide use and individual behaviors are associated with pesticide exposures.

Prenatal Exposure to Ambient Pesticides and Preterm Birth and Term Low Birthweight in Agricultural Regions of California.

Findings from studies of prenatal exposure to pesticides and adverse birth outcomes have been equivocal so far. We examined prenatal exposure to agricultural pesticides in relation to preterm birth and term low birthweight, respectively, in children born between 1998 and 2010, randomly selected from California birth records. We estimated residential exposure to agriculturally applied pesticides within 2 km of residential addresses at birth by pregnancy trimester for 17 individual pesticides and three chemical classes (organophosphates, pyrethroids, and carbamates). Among maternal addresses located within 2 km of any agricultural pesticide application, we identified 24,693 preterm and 220,297 term births, and 4412 term low birthweight and 194,732 term normal birthweight infants. First or second trimester exposure to individual pesticides (e.g., glyphosates, paraquat, imidacloprid) or exposure to 2 or more pesticides in the three chemical classes were associated with a small increase (3–7%) in risk for preterm birth; associations were stronger for female offspring. We did not find associations between term low birthweight and exposure to pesticides other than myclobutanil (OR: 1.11; 95% CI: 1.04–1.20) and possibly the pyrethroids class. Our improved exposure assessment revealed that first and second trimester exposure to pesticides is associated with preterm delivery but is rarely linked with term low birthweight.

Organophosphate pesticide exposure, PON1, and neurodevelopment in school-age children from the CHAMACOS study

IntroductionOrganophosphate (OP) pesticides remain widely used in agriculture. Previously, we reported that PON1 genotype was directly associated with neurodevelopment at age two, and that PON1 genotype may increase susceptibility to OP exposure. ObjectivesWe examined the relationships of maternal and child PON1 genotype and enzyme activity levels and neurodevelopment at school age and examined their interaction with maternal dialkyl phosphate (DAP) metabolite levels to investigate differential susceptibility to OP-related neurotoxicity. MethodsParticipants were from the CHAMACOS longitudinal birth cohort of Latino families in an agricultural region of California. We measured DAP metabolites of OP pesticides in maternal and child urine samples, and analyzed PON1192 and PON1−108 genotypes and enzyme activity [arylesterase (ARYase), paraoxonase (POase)] in maternal and child blood. We examined their association with children׳s performance on the Conners׳ Kiddie Continuous Performance Test (K-CPT) at 5 years (n=296) and the Wechsler Intelligence Scale for Children (WISC-IV) at 7 years (n=327). ResultsMaternal and child PON1 genotype was not related to performance on K-CPT or WISC, although WISC scores tended to be lowest in children and children of mothers who carried the PON−108TT genotype. Pregnancy ARYase levels were positively associated with all WISC subscales (e.g., 4.0 point increase in Full Scale IQ per standard deviation increase in ARYase, 95% CI=1.6, 6.4), while pregnancy POase levels were positively associated with WISC Processing Speed only. Maternal PON1−108 weakly modified the relationship of maternal DAPS and K-CPT scores (pinteraction=0.21) and WISC verbal IQ (pinteraction=0.71). The association between DAPs and Full-Scale IQ was strongest for children of mothers with lowest-tertile ARYase levels (pinteraction=0.27). This relationship held for both diethyl and dimethyl DAPs and for all subscales of the WISC. ConclusionsWe extend our previous findings that PON1 genotype and enzyme levels may be directly related to performance on certain domains of neurodevelopment in school-age children. Lower maternal PON1 enzyme levels during pregnancy may also increase susceptibility of children to neurotoxicity from OP pesticide exposure.

Detections of the Neonicotinoid Insecticide Imidacloprid in Surface Waters of Three Agricultural Regions of California, USA, 2010–2011

Seventy-five surface water samples were collected from three agricultural regions of California and analyzed for the neonicotinoid insecticide imidacloprid. Samples were collected during California's relatively dry-weather irrigation seasons in 2010 and 2011. Imidacloprid was detected in 67 samples (89%); concentrations exceeded the United States Environmental Protection Agency's chronic invertebrate Aquatic Life Benchmark of 1.05 μg/L in 14 samples (19%). Concentrations were also frequently greater than similar toxicity guidelines developed for use in Europe and Canada. The results indicate that imidacloprid commonly moves offsite and contaminates surface waters at concentrations that could harm aquatic organisms following use under irrigated agriculture conditions in California.

Information-Seeking 2.0

This article begins to shed light on how informational advantage affects the use of new media for information-acquisition and assessment. Drawing on material culled from one-on-one and small-group interviews with high school students in an agricultural region of California, the article examines high achievers committed to academic excellence in preparation for college. However, while they share the same educational goals, not all of these students have access to the same informational resources. Informationally advantaged students’ access to new media, traditional media, and social networks distinguishes them from their informationally disadvantaged counterparts who lack access to both online and offline resources. Examination reveals how these disparities in access to informational resources have consequences for the students’ capacity to assess information relevant to schoolwork as well as college planning. Students with plentiful media resources adopt autonomous strategies vis-à-vis the assessment of information for both schoolwork and college searches. By contrast, students without informational resources are forced by necessity to rely on others, ultimately leading them to develop a dependence on trusted opinions in order to assess information. In relating informational environments to these assessment strategies, the article reveals the repercussions of informational advantage for schoolwork and college planning activities increasingly dominated by online resources.

Strivers 2.0: Digital Inequalities, Channel Preferences, &amp; Opportunity Structures

This article begins to shed light on how information capital informs the use of new media for information seeking and evaluation. Drawing on material culled from focus group interviews with high school students in an agricultural region of California, this article examines highly motivated information seekers called “Strivers.” Strivers are committed to academic excellence in preparation for college. However, while they share the same goals, not all Strivers have access to the same informational resources. Access to new media, traditional media, and social networks all contribute to Strivers’ information capital, which in turn informs their encounters with information in online venues. To reveal the deep and deleterious impact of informational inequality as it relates to digital inequality, Strivers are examined in light of their normative access to informational resources. Analysis reveals that Strivers’ use of new media is alternately enhanced or diminished by access to other informational resources used in tandem with digital technologies. Most important, the article reveals that information capital is critical to the development of strategies towards online information seeking and information evaluation. Further, multi-channel information strategies are ultimately internalized by MCIS Agentic Strivers as the ability to evaluate information as experts. By contrast, ERIS Dependent Strivers internalize educator-reliant strategies as necessary to validate information with expert opinions other than their own.

Association of organophosphate pesticide exposure and paraoxonase with birth outcome in Mexican-American women.

BackgroundEpidemiologic studies suggest that maternal organophosphorus (OP) pesticide exposure is associated with poorer fetal growth, but findings are inconsistent. We explored whether paraoxonase (PON1), a key enzyme involved in detoxification of OPs, could be an effect modifier in this association.MethodsThe study population included 470 pregnant women enrolled in the CHAMACOS Study, a longitudinal cohort study of mothers and children living in an agricultural region of California. We analyzed urine samples collected from mothers twice during pregnancy for dialkyl phosphate (DAP) metabolites of OP pesticides. We analyzed maternal and fetal (cord) blood samples for PON1 genotype (PON1192 and PON1−108) and enzyme activity (paraoxonase and arylesterase). Infant birth weight, head circumference, and gestational age were obtained from medical records.ResultsInfants' PON1 genotype and activity were associated with birth outcome, but mothers' were not. Infants with the susceptible PON1−108TT genotype had shorter gestational age (β = −0.5 weeks, 95% Confidence Interval (CI): −0.9, 0.0) and smaller head circumference (β = −0.4 cm, 95% CI: −0.7, 0.0) than those with the PON1−108CC genotype. Infants' arylesterase and paraoxonase activity were positively associated with gestational age. There was some evidence of effect modification with DAPs: maternal DAP concentrations were associated with shorter gestational age only among infants of the susceptible PON1−108TT genotype (p-valueinteraction = 0.09). However, maternal DAP concentrations were associated with larger birth weight (p-valueinteraction = 0.06) and head circumference (p-valueinteraction<0.01) in infants with non-susceptible genotypes.ConclusionsInfants whose PON1 genotype and enzyme activity levels suggested that they might be more susceptible to the effects of OP pesticide exposure had decreased fetal growth and length of gestation. PON1 may be another factor contributing to preterm or low birth weight birth.

INFORMATION-CHANNEL PREFERENCES AND INFORMATION-OPPORTUNITY STRUCTURES

Providing an empirical base to flesh out the notion of ‘information capital’, this article charts the elusive linkages between information-seeking practices, vocational preferences, and information-opportunity structures. Drawing on data from focus group interviews with over 300 advantaged and disadvantaged students, the research examines the information-seeking practices and circumstances of students attending high schools in an agricultural region of California. The article outlines a novel typology of four distinctive information-seeking situations: Internet-reliant information-seeking (IRIS), personal community-reliant information-seeking (PCRIS), educator-reliant information-seeking (ERIS), and multi-channel information-seeking (MCIS). Each of these situations brings together particular information-seeking strategies with specific vocational and educational preferences and particular information-opportunity structures. The four groups of information-seekers exhibit distinctive internalized stances towards what they define as appropriate information-seeking strategies and useful information-channels for educational and career planning. Illustrating these patterns, the article uncovers the connections between students’ educational and career aspirations, on the one hand, and their online and offline information-seeking strategies, on the other hand. By drawing these connections, the analysis provides rich empirical scaffolding for the concepts of information-channel preferences and information-opportunity structures as they relate to information capital, concepts which have remained empirically underdeveloped.

Serum persistent organic pollutants and duration of lactation among Mexican-American women.

Background. Research suggests that estrogenic endocrine-disrupting chemicals interfere with lactation. Objectives. (1) to determine if estrogenic persistent organic pollutants (POPs) are associated with shortened lactation duration; (2) to determine whether previous breastfeeding history biases associations. Methods and Results. We measured selected organochlorines and polychlorinated biphenyls (p, p′-DDE, p, p′-DDT, o, p′-DDT, β-hexachlorocyclohexane, hexachlorobenzene, and PCBs 44, 49, 52, 118, 138, 153, and 180) in serum from 366 low-income, Mexican-American pregnant women living in an agricultural region of California and assessed breastfeeding duration by questionnaires. We found no association between DDE, DDT, or estrogenic POPs with shortened lactation duration, but rather associations for two potentially estrogenic POPs with lengthened lactation duration arose (HR [95% CI]: 0.6 [0.4, 0.8] for p, p′-DDE & 0.8 [0.6, 1.0] for PCB 52). Associations between antiestrogenic POPs (PCBs 138 and 180) and shortened lactation duration were attributed to a lactation history bias. Conclusion. Estrogenic POPs were not associated with shortened lactation duration, but may be associated with longer lactation duration.

Maternal PBDE Exposure and Time to Pregnancy

ISEE-0865 Objective: To examine the association of maternal exposure to polybrominated diphenyl ethers (PBDEs) with time to pregnancy (TTP). Methods: The study population comprised 225 pregnant women participating in the Center for the Health Assessment of Mothers and Children of Salinas (CHAMACOS) study, a cohort study of low-income, predominantly Mexican women living in an agricultural region of California. Concentrations of 10 PBDE congeners were measured in serum collected from the women near the end of the second trimester of pregnancy using gas chromatography and isotope dilution high resolution mass spectrometry. Analyses were limited to four PBDE congeners (BDE-47, −99, −100 and −153) that were detected in more than 75% of women. TTP was defined as the number of months it took to become pregnant, censored at 13 months. Women who were using contraceptives at the time of conception (i.e. contraceptive failures) were excluded. We analyzed the association of TTP with lipid-adjusted PBDEs as continuous variables using discrete-time Cox proportional hazards models, to obtain fecundability odds ratios (fOR). PBDE levels were log transformed and levels below the limit of detection (LOD) were given the values of the LOD/2. All analyzes were adjusted for covariates. Results: Median TTP was 3 months (range: 0–180 months). All four PBDE congeners were associated with longer time to pregnancy (i.e. fOR < 1). Each 10-fold increase in BDE-153 was associated with a 50% decreased odds of conceiving each month (adjusted fOR = 0.5, P = 0.001). Similar results were seen for BDE-47 (adjusted fOR = 0.7, P = 0.05), −99 (adjusted fOR = 0.7, P = 0.08), and −100 (adjusted fOR = 0.6, P = 0.006). Conclusions: Higher maternal PBDE levels during pregnancy were associated with longer time to pregnancy in this population.

Merging Models and Biomonitoring Data to Characterize Sources and Pathways of Human Exposure to Organophosphorus Pesticides in the Salinas Valley of California

We characterize cumulative intakes of organophosphorus (OP) pesticides in an agricultural region of California by drawing on human biomonitoring data, California pesticide use reporting (PUR) data, and limited environmental samples together with outputs from the CalTOX multimedia, multipathway, source-to-dose model. The study population is the CHAMACOS cohort of almost 600 pregnant Latina women in the Salinas Valley region. We use model estimates of OP intake and urinary dialkylphosphate (DAP) metabolite excretion to develop premises about relative contributions from different exposure sources and pathways. We evaluate these premises by comparing the magnitude and variation of DAPs in the CHAMACOS cohort with those of the whole U.S. population using data from the National Health and Nutrition Examination Survey (NHANES). This comparison supports the premise that diet is the common and dominant exposure pathway in both populations. Biomarker comparisons and model results support the observation that, relative to NHANES, the CHAMACOS population has a statistically significant (p < 0.001) added intake of OP pesticides with low inter-individual variability. We attribute the magnitude and small variance of this intake to residential nondietary exposures from local agricultural OP uses. These results show that mass-balance models can estimate exposures for OP pesticides within the range measured by biological monitoring.

The effect of time in the U.S. on the duration of breastfeeding in women of Mexican descent.

Although women of Mexican decent have high rates of breastfeeding, these rates may vary considerably by acculturation level. This study investigated whether increased years of residence in the U.S. is associated with poorer breastfeeding practices, including shorter duration of any and exclusive breastfeeding, in a population of low-income mothers of Mexican descent. Pregnant women (n = 490) were recruited from prenatal clinics serving a predominantly Mexican-origin population in an agricultural region of California. Women were interviewed during pregnancy, shortly postpartum, and when their child was 6 months, 1 year, 2 years, and 3.5 years of age. Increased years of residence in the U.S. was associated with decreased likelihood of initiating breastfeeding and shorter duration of exclusive and any breastfeeding. Median duration of exclusive breastfeeding was 2 months for women living in the U.S. for 5 years or less, 1 month for women living in the U.S. for 6 to 10 years, and less than one week for women living in the U.S. for 11 years or more, or for their entire lives (lifetime residents). After controlling for maternal age, education, marital status and work status, lifetime residents of the U.S. were 2.4 times more likely to stop breastfeeding, and 1.5 times more likely to stop exclusive breastfeeding, than immigrants who had lived in the U.S. for 5 years or less. Efforts are needed to encourage and support Mexican-origin women to maintain their cultural tradition of breastfeeding as they become more acculturated in the U.S.

Soda Consumption and Overweight Status of Two-Year-Old Mexican-American Children

P-483 Introduction: In the United States, child obesity has increased dramatically in the past 30 years. Among 2 to 5 year olds, the prevalence of overweight has increased two-fold, with the highest prevalence reported among Mexican Americans. In parallel with the increase in child obesity, soft drink consumption has also increased. The purpose of this study was to determine the association between current soda consumption and overweight in 2-year-old Mexican-American children. Methods: The CHAMACOS study is a longitudinal study of the health of low-income Latino pregnant women and their children living in an agricultural region of California. Six hundred pregnant women were enrolled between October 1999 and October 2000, and their children were followed until 2 years of age. This cross-sectional analysis includes the 354 children who completed the 2-year follow-up interview. Standing height (cm) and weight (g) were measured at 2 years. Overweight was defined as ≥ 95th percentile of the sex-specific body mass index for each child's age. Results: At 2 years of age, fifty-five (15.5%) children were overweight. Over half (56%) reported consuming any soda in the last seven days, with an average consumption of 0.51 (S.D.= ±0.53) sodas per day. After adjusting for covariates, < 1 soda per day, compared to no soda consumption, was not related to overweight status (adj-OR = 0.97, 95% CI 0.47, 1.99), but ≥1 soda per day was significantly associated with overweight (adj-OR = 3.39, 95% CI 1.43, 8.07) and the test for trend was significant (p = 0.02). Discussion and Conclusions: At 2 years of age, the prevalence of overweight among the CHAMACOS cohort is higher than the national prevalence estimate for Mexican-American, 2–5 year olds, and is significantly associated with current soda consumption. These findings highlight the need for interventions to reduce consumption of soda in preschool-age Mexican-American children.

Seasonal Cropping Pattern Effects on Abundance of Bemisia tabaci (Homoptera: Aleyrodidae) and Incidence of Lettuce Infectious Yellows Virus

The sweetpotato whitefly, Bemisia tabaci (Gennadius), was trapped throughout the southern desert agricultural region of California during two consecutive growing seasons. Trap data revealed changes in whitefly population densities that provide insight into the epidemiology of lettuce infectious yellows virus (LIYV) in fall melon and lettuce. Whitefly abundance increased rapidly from July to September in cotton. During that period, there were significant correlations between number of cotton fields in a region and number of whiteflies trapped in that region. Beginning in August and September, whitefly densities increased in melon, and the proportion of viruliferous whiteflies increased in cotton and melon. After the defoliation of cotton was initiated in September, whiteflies migrated to melons, which not only served as their host but also as a reservoir for LIYV. In October and November high numbers of viruliferous whiteflies were found in melon and lettuce. As melons were harvested and the fields dried, viruliferous whiteflies migrated to newly emerged lettuce.

Assessing continuing education needs of five allied health professions in rural California.

Meeting the needs of rural health care professionals for continuing education remains a challenge for health planners. An assessment of these needs is the focus of this survey of rural practitioners. A continuing education needs survey of five allied health professions in an agricultural region of California was conducted. Variables selected related to professional education and retention and included paramedics, physical therapists, pharmacists, clinical psychologists, and medical technologists. Results indicated a strong need for high quality, moderate cost, locally offered continuing education seminars. Access to professional literature searches was also regarded as important. Several of the selected health profession groups were concerned about maintaining licensure; most intended to remain in their professions for at least six to ten years. These survey findings clearly suggest a need for centrally coordinated continuing education opportunities for allied health personnel in rural service delivery areas.