Skip to main content
eScholarship
Open Access Publications from the University of California

Scholarly Works (15 results)

  • Thesis
  • Peer Reviewed
UCLA Electronic Theses and Dissertations (2013)

Childhood cancer is a rare disease that may be triggered prenatally. The few known causes of pediatric cancers include ionizing radiation, Down syndrome, and some genetic or chromosomal anomalies. Additional risk factors have been suggested, but due to the rarity of childhood cancers, it has been difficult to establish causes and hence targets for prevention. We investigated ultraviolet radiation (UVR), pesticides, and maternal dietary patterns as possible risk and protective factors. Studies have shown that higher solar UVR may be related to lower risk of some cancers in adults and children. In a large, population-based case-control study we tested the hypothesis that childhood cancers may be influenced by UVR. Cancers in children ages 0 to 5 years were identified from California Cancer Registry records for 1988-2007 and linked to birth certificate data. Controls were sampled from birth certificates. Based on birth address, we assigned UVR exposure using a geostatistical exposure model developed with data from the National Solar Radiation Database. Our preliminary findings suggest that UVR during pregnancy may decrease the odds of some childhood cancers. In the same study population we evaluated the associations of exposure to specific pesticide types during pregnancy with glial tumors in young children in California using a validated geographic exposure model. We observed increased odds of astrocytoma for residential pesticide exposure to herbicides, insecticides and fungicides, as well as for several chemical classes of pesticides. Additionally, using data from a multi-institutional case-control study of retinoblastoma in the United States and Canada, we investigated the association of maternal prenatal diet with the risk for unilateral retinoblastoma among children less 15 years of age. Previous studies have shown that mother's diet during pregnancy may affect her offspring's risk of cancer. Our results suggest that a dietary pattern with high fruit and vegetable consumption and low consumption of fried foods and sweets during pregnancy, as well as a dietary pattern with high fruit and vegetable consumption and low consumption of red and cured meats, may reduce the odds of unilateral retinoblastoma in offspring.

    Cover page: Prenatal Risk and Protective Factors for Childhood Cancer: Investigating the Effects of Ultraviolet Radiation, Pesticide Exposure, and Maternal Diet
    • Article
    • Peer Reviewed
    UCLA Previously Published Works (2013)

    Background

    Studies have shown that higher solar UV radiation exposure (UVR) may be related to lower risk of some cancers in adults. Recently, an ecologic study reported lower risks of some cancers among children living in higher UVR cities and countries. In a large population-based case-control study in California, we tested the hypothesis that childhood cancers may be influenced by UVR.

    Methods

    Cancers in children ages 0 to 5 years were identified from California Cancer Registry records for 1988 to 2007 and linked to birth certificate data. Controls were sampled from the birth certificates at a ratio of 20:1. Based on birth address, we assigned UVR exposure in units of Watt-hours/m(2) using a geostatistical exposure model developed with data from the National Solar Radiation Database.

    Results

    For cases with UVR exposure of 5,111 Watt-hours/m(2) or above, we estimated a reduction in odds of developing acute lymphoblastic leukemia (OR: 0.89, 95% CI: 0.81-0.99), hepatoblastoma (OR: 0.69, 95% CI: 0.48-1.00), and non-Hodgkin's lymphoma (OR: 0.71, 95% CI: 0.50-1.02) adjusting for mother's age, mother's race, and child's year of birth. We also observed a small increase in odds for intracranial/intraspinal embryonal tumors (OR: 1.29, 95% CI: 1.01-1.65).

    Conclusions

    Our findings suggest that UVR during pregnancy may decrease the odds of some childhood cancers. Future studies should explore additional factors that may be correlated with UVR exposure and possibly include biomarkers of immune function and vitamin D.

    Impact

    This study shows protective associations of UVR with some childhood cancers.
      • Article
      • Peer Reviewed
      UCLA Previously Published Works (2017)
        Cover page: Maternal Preeclampsia and Odds of Childhood Cancers in Offspring: A California Statewide Case-Control Study
        • Article
        • Peer Reviewed
        UCLA Previously Published Works (2015)

        Purpose

        Previous studies have suggested a role for parental diet in childhood cancer prevention, but there are few studies of retinoblastoma. The aim of this study was to examine the relation between maternal diet and unilateral retinoblastoma.

        Methods

        A case-control study of 163 unilateral RB cases and 136 controls ascertained information on maternal diet during pregnancy using a standardized food frequency questionnaire. Logistic regression was used to assess the relation between retinoblastoma and food groups and dietary patterns.

        Results

        We observed a negative association between retinoblastoma and intake of fruit [odds ratio (OR) 0.38, 95 % confidence interval (CI) 0.14-1.02]. Positive associations were seen with intake of cured meats (OR 5.07, 95 % CI 1.63-15.70) and fried foods (OR 4.89, 95 % CI 1.72-13.89). A food pattern of high fruits and vegetables and low fried food and sweets was negatively associated with disease (OR 0.75, 95 % CI 0.61-0.92).

        Conclusion

        Our study provides preliminary evidence that mothers who consume diets higher in fruit and lower in fried foods and cured meats during pregnancy may reduce the risk of unilateral retinoblastoma in their offspring.
          • Article
          • Peer Reviewed
          UCLA Previously Published Works (2021)
          Background:

          Pesticide exposures have been examined previously as risk factors for childhood brain cancers, but few studies were able to assess risk from specific agents.

          Objective:

          To evaluate risks for childhood central nervous system tumors associated with residential proximity to agricultural pesticide applications.

          Methods:

          Using the California Cancer Registry, we identified cancer cases less than 6 years of age and frequency matched them by year of birth to 20 cancer-free controls identified from birth certificates. We restricted analyses to mothers living in rural areas and births occurring between 1998 and 2011, resulting in 667 cases of childhood central nervous system tumors and 123,158 controls. Possible carcinogens were selected per the Environmental Protection Agency’s (US. EPA) classifications, and prenatal exposure was assessed according to pesticides reported by the California Department of Pesticide Regulation’s (CDPR) Pesticide Use Reporting (PUR) system as being applied within 4000m of the maternal residence at birth. We computed odds ratios for individual pesticide associations using unconditional logistic and hierarchical regression models.

          Results:

          We observed elevated risks in the hierarchical models for diffuse astrocytoma with exposure to bromacil (OR: 2.12, 95% CI: 1.13-3.97), thiophanate-methyl (OR: 1.64, 95% CI: 1.02-2.66), triforine (OR: 2.38, 95% CI: 1.44-3.92), and kresoxim methyl (OR: 2.09, 95% CI: 1.03-4.21); elevated risks for medulloblastoma with exposure to chlorothalonil (OR: 1.78, 95% CI: 1.15-2.76), propiconazole (OR: 1.60, 95% CI: 1.02, 2.53), dimethoate (OR: 1.60, 95% CI: 1.06, 2.43), and linuron (OR: 2.52, 95% CI: 1.25, 5.11); and elevated risk for ependymoma with exposure to thiophanate-methyl (OR: 1.72, 95% CI: 1.10-2.68).

          Conclusion:

          Our study suggests that exposure to certain pesticides through residential proximity to agricultural applications during pregnancy may increase the risk of childhood central nervous system tumors.

            Cover page: Residential Proximity to Pesticide Application as a Risk Factor for Childhood Central Nervous System Tumors
            • Article
            Recent Work (2008)

            Despite advances in therapy, asthma remains a disease that is not optimally controlled in many Californians. This policy brief examines the economic and social burden of the poor control of asthma and recommends policy changes to reduce those costs. Using data from the California Health Interview Survey (CHIS), the authors found that California's children missed 1.9 million days of school and the state's adult workers missed 2 million days of work due to asthma. As many as 475,000 children and adults in California reported that they went at least once to the emergency room or urgent care center because of asthma. The number is likely to be much higher due to repeat visits. The research adds to a growing body of knowledge about the debilitating personal and economic effects of asthma, a condition linked to pollution, lack of insurance and medical care as well as to risk factors such as smoking.

              Cover page: Uncontrolled Asthma Means Missed Work and School, Emergency Department Visits for Many Californians
              • Article
              • Peer Reviewed
              UCLA Previously Published Works (2012)

              Purpose

              The etiology of retinoblastoma remains poorly understood. In the present study, we examined associations between perinatal factors and retinoblastoma risk in California children.

              Methods

              We identified 609 retinoblastoma cases (420 unilateral, 187 bilateral, and 2 with laterality unknown) from California Cancer Registry records of diagnoses 1988-2007 among children < 6 years of age. We randomly selected 209,051 controls from California birth rolls. The source of most study data was birth certificates. Multivariable logistic regression was used to examine associations between retinoblastoma and perinatal characteristics.

              Results

              Bilateral retinoblastoma was associated with greater paternal age [for fathers over 35, crude odds ratio (OR) = 1.73, 95 % confidence interval (CI) 1.20, 2.47] and with twin births (OR = 1.93, 95 % CI 0.99, 3.79). Among unilateral cases, we observed an increased risk among children of US-born Hispanic mothers (OR = 1.34, 95 % CI 1.01, 1.77) while a decreased risk was observed for infants born to mothers with less than 9 years of education (OR = 0.70, 95 % CI 0.49, 1.00), a group that consisted primarily of mothers born in Mexico. We observed that maternal infection in pregnancy with any STD (OR = 3.59, 95 % CI 1.58, 8.15) was associated with bilateral retinoblastoma.

              Conclusions

              This study supports the findings of previous investigations reporting associations between parental age, HPV infection, and retinoblastoma.
                • Article
                Recent Work (2008)

                Despite advances in therapy, asthma remains a disease that is not optimally controlled in many Californians. This policy brief examines the economic and social burden of the poor control of asthma and recommends policy changes to reduce those costs. Using data from the California Health Interview Survey (CHIS), the authors found that California's children missed 1.9 million days of school and the state's adult workers missed 2 million days of work due to asthma. As many as 475,000 children and adults in California reported that they went at least once to the emergency room or urgent care center because of asthma. The number is likely to be much higher due to repeat visits. The research adds to a growing body of knowledge about the debilitating personal and economic effects of asthma, a condition linked to pollution, lack of insurance and medical care as well as to risk factors such as smoking.

                  Cover page: Uncontrolled Asthma Means Missed Work and School, Emergency Department Visits for Many Californians
                  • Article
                  • Peer Reviewed
                  UCLA Previously Published Works (2010)
                  Maternal psychosocial stress is an important risk factor for preterm birth, but support interventions have largely been unsuccessful. The objective of this study is to assess how support during pregnancy influences preterm birth risk and possibly ameliorates the effects of chronic stress, life event stress, or pregnancy anxiety in pregnant women. We examined 1,027 singleton preterm births and 1,282 full-term normal weight controls from a population-based retrospective case–control study of Los Angeles County, California women giving birth in 2003, a mostly Latina population (both US-born and immigrant). We used logistic regression to assess whether support from the baby’s father during pregnancy influences birth outcomes and effects of chronic stress, pregnancy anxiety, and life event stress. Adjusted odds of preterm birth decreased with better support (OR 0.73 [95%CI 0.52, 1.01]). Chronic stress (OR 1.46 [95%CI 1.11, 1.92]), low confidence of a normal birth (OR 1.57 [95% CI 1.17, 2.12]), and fearing for the baby’s health (OR 1.67 [95%CI 1.30, 2.14]) increased preterm birth risk, but life events showed no association. Our data also suggested that paternal support may modify the effect of chronic stress on the risk of preterm birth, such that among mothers lacking support, those with moderate-to-high stress were at increased odds of delivering preterm (OR 2.15 [95%CI 0.92, 5.03]), but women with greater support had no increased risk with moderate-to-high chronic stress (OR 1.13 [95%CI 0.94, 1.35]). Paternal support may moderate the effects of chronic stress on the risk of preterm delivery.
                    Cover page: Paternal support and preterm birth, and the moderation of effects of chronic stress: a study in Los Angeles County mothers
                    • Article
                    • Peer Reviewed
                    UCLA Previously Published Works (2013)

                    Background

                    Rhabdoid tumors are a rare and aggressive cancer subtype which is usually diagnosed in early childhood. Little is known about their etiology. The purpose of this study was to describe the epidemiology of rhabdoid tumors and examine their relation to perinatal characteristics.

                    Methods

                    We identified 44 atypical teratoid/rhabdoid tumors (AT/RT) of the central nervous system (CNS) and 61 rhabdoid sarcomas (renal and extra-renal non-CNS tumors) from California Cancer Registry records of diagnoses 1988-2007 among children <6 years of age. We randomly selected 208,178 controls from California birthrolls. Multivariable logistic regression was used to examine associations between rhabdoid tumors and perinatal characteristics.

                    Results

                    After adjustment for demographic characteristics, low birthweight (<2,500 g) strongly increased risk for developing both rhabdoid sarcomas (OR = 2.43, 95% CI 1.09, 5.41) and AT/RT (OR = 2.99, 95% CI 1.31, 6.84). Both preterm delivery (<37 weeks gestation, OR = 2.63, 95% CI 1.34, 5.17) and late term delivery (>42 weeks, OR = 3.66, 95% CI 1.54, 8.71) also increased risk of rhabdoid sarcomas. Rhabdoid sarcoma cases (OR = 3.08, 95% CI 1.11, 8.55) and AT/RT cases (OR = 3.16, 95% CI 1.23, 8.13) also were more likely to be multiple births.

                    Conclusion

                    The excess of twin pregnancies may suggest an association with infertility treatments. This is the first population-based epidemiologic study to examine these rare tumors.
                      Top