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Susan Preston-Martin

Publications and source records attributed to Susan Preston-Martin.

35 records · Page 2Linked to original sources
PubMed2003

Maternal prenatal exposure to nitrosatable drugs and childhood brain tumours.

BACKGROUND: A compelling hypothesis was proposed that childhood brain tumours are associated with maternal exposure to N-nitroso compounds during the prenatal period. Many common drugs, such as antihistamines, aspirin, and antibiotics, are nitrosatable and depending upon the product, potentially carcinogenic. We hypothesized that maternal ingestion of certain subgroups of nitrosatable drug products during pregnancy increases the risk of brain tumour development in offspring. METHODS: Data were collected as part of a population-based case-control study of childhood brain tumours and mothers' self-reported exposure to therapeutic drugs and dietary nitrites. Cases were enrolled from three US West Coast SEER tumour registries: Seattle-Puget sound, Los Angeles County, and the San Francisco-Oakland Bay Area. Tumours were grouped into three major histological tumour subtypes: astroglial, primitive neural ectodermal tumours, and all remaining glial tumours ('other glial'). Therapeutic drugs reported by mothers were translated into active chemical compounds and classified as secondary amines, tertiary amines, amides, or none of the three. Risk estimates were computed according to classes of nitrosatability, potential carcinogenicity, teratogenicity, and predicted end product. RESULTS: We found no significant association between maternal use of nitrosatable drugs, either overall or within any of the nitrosatable drug classifications, and subsequent development of brain tumours in children. Nitrite consumption from cured meats was not an effect modifier. However, exposure to nitrosoephedrine during pregnancy was associated with significantly increased risk of 'other glial' tumours (OR = 3.1; 95% CI: 1.1-9.2). CONCLUSIONS: These findings do not support an association between maternal use of nitrosatable drugs during pregnancy and brain tumour risk in offspring. While exposure to the nitrosation end product nitrosoephedrine was associated with increased risk for other glial tumours, the finding was not specific to any one type of tumour.

Adolescent↗
PubMed2003

Estimation of radiographic doses in a case-control study of acute myelogenous leukemia.

Radiation exposure from dental and medical radiography is inherently difficult to estimate. Because no single resource is available for this type of data, gathering the information needed to estimate exposure in epidemiologic studies is a labor-intensive, imprecise process. For a case-control study of adult-onset acute myelogenous leukemia in Los Angeles County and radiography, a database was created of estimates of dose to the red bone marrow for each radiographic procedure reported by subjects in interviews and recorded in subjects' medical records. Resources used included the medical literature as well as personal communications with radiology experts. Dose estimates for each procedure based on this database are reported. Methods and complications are contrasted with a past effort to estimate dose from dental radiography for a case-control study of parotid gland tumors. Among the more difficult aspects of medical radiography dose estimation are the wide variety of examinations performed, the continually-changing environment of diagnostic imaging, and the number of variables that contribute to the delivered dose to an individual from a specific imaging procedure.

Body Burden↗
PubMed2003

Psychometric performance of the NEI VFQ-25 in visually normal Latinos: the Los Angeles Latino Eye Study.

PURPOSE: To characterize the psychometric performance of the National Eye Institute 25-item Visual Function Questionnaire (NEI VFQ-25) in visually normal Latinos (Mexican Americans). METHODS: The Los Angeles Latino Eye Study (LALES) is a population-based study to assess the prevalence of eye disease and self-reported visual functioning in Latinos aged 40 or more years. Self-reported visual functioning was assessed by using English and Spanish versions of the NEI VFQ-25. Psychometric properties of the NEI VFQ-25, including internal consistency of the subscales and the individual items, were assessed through the Multi-trait Analysis Program-Revised (MAP-R) analysis. Adjusted mean and median subscale scores were compared between English and Spanish speakers to identify any systematic differences. RESULTS: Of the 1917 participants from two census tracts, 1171 participants with no visual impairment were included in this analysis. The mean age of the participants was 52.3 years, 57% of the participants were female, and 67.5% of the participants were Spanish speaking. Median scores for Spanish-speaking participants were significantly lower than those of the English-speaking participants on four subscales: Ocular Pain, General Vision, Vision-Specific Mental Health, and General Health (P < 0.05). Internal consistency for three of eight measurable subscales for the study group was poor (Cronbach alpha < 0.6). CONCLUSIONS: This study reveals psychometric inconsistencies in the NEI VFQ-25 when administered to visually normal Latinos. The difference in mean subscale scores between Spanish and English speakers must be integrated into the development of population norms of visual function. Further detailed psychometric evaluation is needed to determine the validity of this instrument in Latino populations.

Activities of Daily Living↗
PubMed2002

Relation of childhood brain tumors to exposure of parents and children to tobacco smoke: the SEARCH international case-control study. Surveillance of Environmental Aspects Related to Cancer in Humans.

The etiology of childhood brain tumors (CBTs) remains unknown. Tobacco smoke contains several known carcinogens and can induce DNA adducts in human placenta and hemoglobin adducts in fetuses. We present the results of an international case-control study to evaluate the association between CBTs and exposure of parents and children to cigarette smoke. The study was undertaken as part of the SEARCH program of the IARC. Nine centers in 7 countries were involved. The studies mainly covered the 1980s and early 1990s. Cases (1,218, ages 0-19 years) were children newly diagnosed with a primary brain tumor; there were 2,223 population-based controls. Most mothers who agreed to participate were interviewed in person at home. Odds ratios (ORs) were calculated by unconditional logistic regression, adjusted for age, sex and center, for all types of CBT combined, 4 CBT histotypes, 5 age groups and each center. There was no association between the risk of brain tumors in the child and parental smoking prior to pregnancy, maternal smoking or regular exposure to others' cigarette smoke during pregnancy at home or at work, or passive smoking by the child during the first year of life. These results did not change considering the child's age at diagnosis, the histologic type of tumor or center.

Adolescent↗
PubMed2002

Smoking and risk of acute myeloid leukemia: results from a Los Angeles County case-control study.

Acute myelogenous leukemia (AML) is a heterogeneous disease with distinct histologic subtypes likely to have distinct risk factors. The authors examined smoking and the risk of adult AML by French-American-British (FAB) subtype in a Los Angeles County, California, population-based case-control study of 412 cases diagnosed between 1987 and 1994 and 412 matched controls. Consistent with previous studies, smoking was not a substantial risk factor for AML overall (odds ratio (OR) = 1.2, 95% confidence interval (CI): 0.9, 1.6). However, increased risk was observed for FAB subtype M2 (OR = 2.3, 95% CI: 1.1, 4.4), particularly for subjects aged 60-75 years (OR = 3.3, 95% CI: 1.1, 10.0). For M2, significant dose-response was associated with total years smoked (p = 0.02), cigarettes per day (p = 0.007), and product filter status (filtered vs. nonfiltered; p = 0.03). The authors estimate that 42% (standard error = 13%) of M2 cases are attributable to smoking. There were no or weak associations between smoking and increased AML risk for other FAB subtypes. The finding by this study of an association between smoking and FAB subtype M2 confirms a previously published report and suggests that earlier findings of no or weak smoking-AML associations may have been due to lack of subtype-specific analysis.

Acute Disease↗
PubMed2002

Use of mammographic screening by HIV-infected women in the Women's Interagency HIV Study (WIHS).

BACKGROUND: Although HIV-positive women may be less likely than women in general to receive mammography due to socioeconomic disadvantage, HIV diagnosis may increase opportunities for medical interactions which encourage mammography. METHODS: HIV-positive (2,059) and HIV-negative (569) Women's Interagency HIV Study (WIHS) participants reported ever/never history of mammography at baseline (in 1994, 1995) and, at each 6-month follow-up visit, if they had been screened since their last visit. National Health Interview Survey (NHIS) data for 1994 were used to compare WIHS participants to U.S. women. Factors independently related to mammography were determined using logistic regression for baseline data and proportional hazards for follow-up data. Results were adjusted for age. RESULTS: Among women > or =40, fewer WIHS women, regardless of HIV status, reported screening than U.S. women (67% HIV-positive, 62% HIV-negative, 79% NHIS; P < 0.0001). First-time screening while on study was associated with being HIV-positive [rate ratio (95% confidence interval) = 1.6 (1.1, 2.3)]. Factors independently associated with screening were related to health care access and usage. CONCLUSIONS: WIHS women, a disadvantaged population, reported less mammography than the general population. HIV-positive women reported more screening than HIV-negative women, possibly because of greater opportunity to interact with the health care system.

Adult↗
PubMed2002

Lifestyle and other risk factors for thyroid cancer in Los Angeles County females.

PURPOSE AND METHODS: We conducted a population-based case-control study of thyroid cancer. Cases were 292 women, aged 15-54 when diagnosed between the years 1980 and 1983 (145 diagnosed in 1980-81 and 147 diagnosed in 1982-83). Female neighborhood controls (n = 292) were matched to each case on birth-year and race. RESULTS: Among women < 35 years, thyroid disease in first-degree relatives increased thyroid cancer risk [odds ratio (OR) = 2.0, 95% confidence interval (CI) = 1.1-3.7]. Risk was not associated with fish consumption, although high childhood consumption of shellfish decreased thyroid cancer risk (OR = 0.2, 95% CI = 0.05-0.7 for consumption at least a few times weekly). Among papillary thyroid cancers (82% of cases), frequent adult consumption of saltwater fish decreased risk. Cancer risk was reduced with consumption of certain vegetables, wine, and tea. Other dietary variables, including milk, beer and hard liquor, and coffee were not related to thyroid cancer risk. Among the papillary sample, risk increased with longer use of multivitamins (OR = 2.9, 95% CI = 1.2-7.4 for > 10 years of use). Smoking and body mass were not associated with thyroid cancer risk. CONCLUSIONS: These results suggest a role of family history of thyroid disease and certain dietary variables in the etiology of thyroid cancer in adult females.

Adolescent↗
PubMed2002

Sinonasal cancer and occupational exposures: a pooled analysis of 12 case-control studies.

OBJECTIVE: In order to examine the associations between sinonasal cancer and occupational exposures other than wood dust and leather dust, the data from 12 case-control studies conducted in seven countries were pooled and reanalyzed. METHODS: The pooled data set included 195 adenocarcinoma cases (169 men and 26 women), 432 squamous cell carcinomas (330 men and 102 women), and 3136 controls (2349 men and 787 women). Occupational exposures to formaldehyde, silica dust, textile dust, coal dust, flour dust, asbestos, and man-made vitreous fibers were assessed with a job-exposure matrix. Odds ratios (ORs) were adjusted for age, study, wood dust, and leather dust, or other occupational exposures when relevant. 95% confidence intervals (CIs) were estimated by unconditional logistic regression. RESULTS: A significantly increased risk of adenocarcinoma was associated with exposure to formaldehyde. The ORs for the highest level of exposure were 3.0 (Cl = 1.5-5.7) among men and 6.2 (CI=2.0-19.7) among women. An elevated risk of squamous cell carcinoma was observed among men (OR=2.5, CI=0.6-10.1) and women (OR = 3.5, CI = 1.2-10.5) with a high probability of exposure to formaldehyde. Exposure to textile dust was associated with non-significantly elevated risk of adenocarcinoma, among women only: the OR for the high level of cumulative exposure was 2.5 (CI = 0.7-9.0). High level of asbestos exposure was associated with a significantly increased risk of squamous cell carcinoma among men (OR = 1.6, CI = 1.1-2.3). CONCLUSIONS: The results of this pooled analysis support the hypothesis that occupational exposure to formaldehyde increases the risk of sinonasal cancer, particularly of adenocarcinoma. They also indicate an elevated risk of adenocarcinoma among women exposed to textile dust, and suggest that exposure to asbestos may increase the risk of squamous cell carcinoma.

Adenocarcinoma↗
PubMed2002

Risk factors for medullary thyroid carcinoma: a pooled analysis.

OBJECTIVE: To investigate risk factors for medullary thyroid cancer (MTC). METHODS: We conducted a pooled analysis of 14 case-control studies from Europe, North America, and Asia, including 67 medullary cancers (43 women and 24 men) diagnosed in ten studies. Of the original 4776, we selected five controls per case matched on study, gender, and age. The pooled odds ratios (OR) were estimated using conditional logistic regression. RESULTS: Education, weight, and body mass were not associated with MTC, but a significant positive relationship was seen with height (OR = 2.6 for highest vs lowest tertile). Significant excess risks were associated with a history of thyroid nodules (OR = 12), hypertension (OR = 2.3), gallbladder disease (OR = 4.3), and allergies (OR = 2.2). Among current smokers, a decreased risk of MTC was observed with increasing number of cigarettes. The risk was significantly elevated among women having a first birth after age 25 years, but no clear pattern emerged for other reproductive factors. CONCLUSIONS: Although the number of MTC was small, we detected several significant associations, including prior thyroid and other diseases.

Adult↗
PubMed2002

Medical radiation, family history of cancer, and benign breast disease in relation to breast cancer risk in young women, USA.

OBJECTIVE: In previous studies breast cancer risk has been increased among women who received high doses (above 100-200 cGy) of ionizing radiation or those exposed to lower doses prior to age 20. Some evidence suggests that such risk may be distinctly elevated among women with a family history of breast or ovarian cancer (probably only carriers of specific gene mutations) and women with benign breast disease (BBD). METHODS: A population-based case-control study in Los Angeles County obtained interview data from 744 women who were aged 40 or younger and diagnosed with breast cancer during 1983-1988, and from 744 matched controls. Women with a positive family history of breast or ovarian cancer reported cancer in a mother, sister, or grandmother. Women with BBD reported a physician diagnosis. Radiation exposure was defined as a history of either radiation therapy or moderate exposure to medical radiography. RESULTS: Breast cancer risk was elevated among women exposed to medical radiation prior to age 20 years (odds ratio (OR) = 1.4, 95% confidence interval (CI) = 1.2-1.8), relative to unexposed women. This increased risk was observed only among women with a history of BBD (OR = 2.4, 95% CI = 1.6-3.7). Overall, risk was not associated with exposure to medical radiation after age 20 years, although among women with a positive family history of breast or ovarian cancer, exposed women had an increased risk (OR= 1.8, 95% CI = 1.0-3.1). Breast cancer risk was not increased among women with a family history of breast/ovarian cancer exposed to medical radiation before age 20 years or those with BBD exposed to medical radiation after age 20 years. DISCUSSION: Study participants may have received radiation doses that are no longer common, hampering study generalizability. Although differences in recall between cases and controls cannot be completely excluded, women with BBD or a family history of breast cancer appear to have greater breast cancer risk following relatively low ionizing radiation exposure than other women in this study.

Adult↗
PubMed2002

A pooled analysis of case-control studies of thyroid cancer. VII. Cruciferous and other vegetables (International).

OBJECTIVE: To investigate the association between cruciferous and other vegetables and thyroid cancer risk we systematically reanalyzed the original data from 11 case-control studies conducted in the US, Asia, and Europe. METHODS: A total of 2241 cases (1784 women, 457 men) and 3716 controls (2744 women, 972 men) were included. Odds ratios (OR) and the corresponding 95% confidence intervals (CI) were estimated for each study by logistic regression models, conditioned on age and sex, and adjusted for history of goiter, thyroid nodules or adenomas, and radiation. Summary ORs for all studies combined were computed as the weighted average of the estimates from each study. RESULTS: A decreased risk for the highest level of cruciferous vegetable intake, as compared to the lowest, was observed in Los Angeles, Hawaii, Connecticut, southeastern Sweden, Tromsø, and Switzerland; the OR were above unity in Japan and Uppsala, whereas no material association was found in northern Sweden, Italy, or Greece. The OR values for all studies combined were 0.87 (95% CI 0.75-1.01) for moderate and 0.94 (95% CI 0.80-1.10) for high cruciferous vegetables intake. The results were similar in studies from iodine-rich areas and endemic goiter areas, and were consistent when the analysis was restricted to papillary carcinomas and women. The summary OR values for vegetables other than cruciferous were 1.04 (0.88-1.22) for moderate and 0.82 (0.69-0.98) for high consumption. CONCLUSIONS: This combined analysis indicates that cruciferous vegetables are not positively related to thyroid cancer risk. Their effect does not seem to be substantially different from that of other vegetables, which appear to be protective on this cancer.

Brassica↗
PubMed2002

West Coast study of childhood brain tumours and maternal use of hair-colouring products.

The immature nervous system of the fetus is characterised by rapid cell growth and division and is particularly vulnerable to carcinogens and mutagens. Several epidemiological studies have reported an increased risk for childhood brain tumours (CBT) associated with exposure to N-nitroso compounds (NOC). Hair-colouring products (hair "dyes") that contain NOC-related aromatic amines have shown mutagenicity in vitro and carcinogenic properties in vivo. The potential public health impact of the relationship between hair dye use and carcinogenesis has prompted epidemiological research, given that a large proportion of American women have used hair dyes. A large population-based case-control study was conducted on the west coast of the USA to investigate risk factors for CBT including exposure to NOC. Eligible CBT patients (<20 years of age and diagnosed between 1984 and 1991) were identified from cancer registries in Los Angeles County, the San Francisco Bay Area in California and the Seattle area in Washington state. A total of 540 biological mothers of these children were interviewed, and 801 control subjects who were frequency matched to the CBT patients on birth year and sex were obtained using random digit dialling. Mothers were asked details about personal use of hair dyes during the index pregnancy including frequency of use, trimester of use and type of dye used. Results from age- and sex-adjusted unconditional logistic regression analyses showed no association between risk for CBT and use of hair dyes 1 month before and/or during pregnancy nor during specific trimesters. A nearly twofold increased risk for CBT was associated with single-interval use during the 1 month before pregnancy, but the confidence interval (CI) was imprecise and the estimate was not different from unity (OR = 1.9, 95% CI [0.5, 7.0]). Exclusive use of permanent dye, temporary dye or hair darkeners was not associated with risk for CBT. A twofold increased risk (OR = 2.0, 95% CI [0.83, 4.7]) was observed with exclusive use of semi-permanent dye during the month before or during pregnancy. Exclusive use of semi-permanent dye during the month before pregnancy and/or first trimester also was associated with an elevated risk for CBT, again not different from unity and with an imprecise CI (OR = 2.5, 95% CI = [0.58, 10.3]). There was no evidence of an association between risk for CBT by histological subtypes and use of hair dyes during the index pregnancy or the month before conception. Together with results from previous studies, these results provide no consistent evidence of an association between risk for CBT and use of hair dyes during pregnancy.

Adolescent↗
PubMed2002

The potential impact of incomplete radiography histories in epidemiologic studies that rely on prepaid health plan records.

Members of prepaid health plans are often considered a group for which complete histories of exposure to medically-related risk factors are known. In a population-based case-control study of radiography as a risk factor for acute myelogenous leukemia, extensive retrospective exposure data from an average of 71% of subjects' health care providers were collected. It was determined that at least 21% of prepaid health plan members received diagnostic imaging procedures outside of their plans over the 10-y period of interest and that these "outside" procedures constituted 43% of their total red bone marrow dose from all radiographic imaging. Procedures significantly more likely to have been received outside of prepaid health plans were conventional spine x rays (p = 0.004) and coronary angiograms (p < 0.0001). All "outside" coronary angiograms and 50% of "outside" spine x rays were received at hospitals. Epidemiologic studies that restrict exposure to that received within prepaid health plans may miss a substantial portion of exposure, resulting in underestimated risk estimates and a loss of statistical power.

Adult↗
PubMed2002

Radiation exposure from diagnostic imaging: agreement between self-report and medical records.

Data on diagnostic imaging procedures from a highly structured interview were compared to medical records in a case-control study of radiography and acute myelogenous leukemia. Three hundred and twenty-eight cases and 315 controls (78% of participants) had medical records available from an average of 71% of providers. Proxies were used for 49% of cases because of rapid fatality. Mean agreement (number of procedures in medical records subtracted from number in interview) showed similar levels of overreporting in cases [0.6; 95% confidence interval (CI): 0.0, 1.1] and controls (0.7; CI: 0.2, 1.3) with few procedures (<= 10). Most participants with more procedures underreported exposure, and underreporting increased with increasing exposure, especially among cases [mean (CI) agreement = -2.1 (-4.3, 0.0) for 11-20 procedures, -6.4 (-13.6, 0.7) for >20 procedures] and case proxies. High-dose, fluoroscopic, and non-routine procedures were self-reported more accurately than low-dose, non-fluoroscopic, and routine procedures, respectively (p < 0.01 for each comparison), and tended to be underreported. Case-control differences in agreement were non-significant for these categories of procedures. We conclude that diagnostic imaging procedures of most interest to the AML-radiography hypothesis are self-reported accurately but that underreporting does occur and might lead to attenuated risk estimates.

Bone Marrow↗
PubMed2002

Using focus groups to develop a culturally sensitive methodology for epidemiological surveys in a Latino population: findings from the Los Angeles Latino Eye Study (LALES).

BACKGROUND: Many standardized survey instruments are initially developed in English-speaking populations. These instruments may not be culturally appropriate for other ethnic groups, such as Latinos. METHODS: The Los Angeles Latino Eye Study (LALES) was designed to determine the prevalence of blindness, visual impairment, and ocular diseases; risk factors for these diseases; and general and ocular healthcare use among non-institutionalized adult Latinos in suburban Los Angeles County, California. The LALES investigators used focus groups to develop questionnaires and to devise culturally sensitive methods for implementing this epidemiologic study in a Latino population. Eighty-four respondents were administered the in-home questionnaire and then scheduled into one of 6 in-home focus groups, allowing participants to reflect in groups about the study, their participation, and the state of the instruments and the translations. FINDINGS: Overall, respondents reported that the questionnaire was well written, easy to understand, and very clear. Recommendations from participants included: 1) keep questions brief; 2) minimize the number of response choices; 3) keep phrasing clear; 4) simplify technical terms; 5) provide test results immediately after the clinical examination; and 6) hire Spanish-speaking staff to increase participants' trust and confidence. CONCLUSION: Focus groups assisted in yielding a culturally appropriate survey research tool and methodology for this population-based study in a Latino community.

Adult↗
PubMed2002

Binocular visual acuity summation and inhibition in an ocular epidemiological study: the Los Angeles Latino Eye Study.

PURPOSE: To characterize binocular visual acuity summation and inhibition in participants of a population-based ocular epidemiologic study. METHODS: A complete ophthalmic examination of Latinos, aged 40 or more years, measured binocular and monocular distance visual acuities by a standard early-treatment diabetic retinopathy study (ETDRS) protocol. The proportions of participants who demonstrated binocular summation (i.e., binocular visual acuity was better than the better eye visual acuity by five or more letters), binocular inhibition (i.e., binocular visual acuity was worse than the better eye visual acuity by five or more letters), and visual impairment (visual acuity worse than 20/40) were calculated. RESULTS: In 1831 individuals, on average, binocular visual acuity was better than better eye visual acuity. Prevalence rates of binocular summation and inhibition were 21% and 2%, respectively. Compared with participants less than 65 years old or those with equivalent interocular visual acuity, older participants (> or =65 years) and those with interocular differences in visual acuity were more likely to demonstrate binocular inhibition (P < 0.01). The rate of visual impairment was significantly lower, when using binocular visual acuity than when using better eye or the American Medical Association (AMA) algorithm (5.2% vs. 6.9% and 9.5%, respectively P < 0.01). Participants with binocular inhibition had greater self-reported problems with driving activities (P < 0.05). CONCLUSIONS: The large proportion of individuals demonstrating binocular summation and inhibition suggests that in clinical or research settings, binocular visual acuity should be considered a primary measure of visual impairment, because it better equates the state in which the person usually functions.

Adult↗