Household exposure to pesticides and risk of childhood hematopoietic malignancies: The ESCALE study (SFCE)

OBJECTIVES: We investigated the role of household exposure to pesticides in the etiology of childhood hematopoietic malignancies. METHODS: The national registry-based case-control study ESCALE (Etude sur les cancers de l'enfant) was carried out in France over the period 2003-2004. Population controls were frequency matched with the cases on age and sex. Maternal household use of pesticides during pregnancy and paternal use during pregnancy or childhood were reported by the mothers in a structured telephone questionnaire. Insecticides (used at home, on pets, or for garden crops), herbicides, and fungicides were distinguished. We estimated odds ratios (ORs) using unconditional regression models closely adjusting for age, sex, degree of urbanization, and type of housing (flat or house). RESULTS: We included a total of 764 cases of acute leukemia (AL), 130 of Hodgkin lymphoma (HL), 166 of non-Hodgkin lymphoma (NHL), and 1,681 controls. Insecticide use during pregnancy was significantly associated with childhood AL [OR = 2.1; 95% confidence interval (CI), 1.7-2.5], both lymphoblastic and myeloblastic, NHL (OR = 1.8; 95% CI, 1.3-2.6), mainly for Burkitt lymphoma (OR = 2.7; 95% CI, 1.6-4.5), and mixed-cell HL (OR = 4.1; 95% CI, 1.4-11.8), but not nodular sclerosis HL (OR = 1.1; 95% CI, 0.6-1.9). Paternal household use of pesticides was also related to AL (OR = 1.5; 95% CI, 1.2-1.8) and NHL (OR = 1.7; 95% CI, 1.2-2.6); but for AL the relationships did not remain after adjustment for maternal pesticide use during pregnancy. CONCLUSION: The study findings strengthen the hypothesis that domestic use of pesticides may play a role in the etiology of childhood hematopoietic malignancies. The consistency of the findings with those of previous studies on AL raises the question of the advisability of preventing pesticide use by pregnant women.     

Burn-related physical impairments and disabilities in Ghanaian children: prevalence and risk factors.

The prevalence, and risk factors for childhood burn-related physical impairments and disabilities in Ghana were determined with data from mothers of burned children. Of 650 identified burns 113 (174%) resulted in physical impairments, 5 (1%) resulted in physical disabilities. After multivariate adjustment, the odds of developing burn-related physical impairments were increased by burns with protracted healing (odds ratio [OR] = 5.80), burns to the head/neck (OR = 344), burns involving skin removal (OR = 3.04), and wound infection (OR = 2.03) and decreased by first aid (OR = 0.51) and maternal education (OR = 0.54). Education on the proper care of burns may prevent burn-related physical impairments. The results also underscore the link between maternal education and child morbidity.     

Early child-care and preschool experiences and the risk of childhood acute lymphoblastic leukemia

An infectious etiology for childhood acute lymphoblastic leukemia (ALL) has been suggested, yet few studies have focused on the role of early child care. Day-care histories were examined in a case-control study of ALL in New York State. Cases (n = 255) were diagnosed at one of four referral centers between 1980 and 1991; controls (n = 760) were randomly selected from livebirths in the 31 counties served by the referral centers. Self-administered questionnaires were mailed to the parents of cases and controls in 1995. Day-care histories were censored at the age of diagnosis for cases and at an equivalent date for controls. The odds ratio for children who stayed at home compared with those who attended day care for >36 months was 1.32 (95% confidence interval (CI): 0.70, 2.52); the odds ratios for 1-18 and 19-36 months of day care were 1.74 (95% CI: 0.89, 3.42) and 1.32 (95% CI: 0.64, 2.71), respectively. Elimination of cases with T-cell ALL enhanced the risk. Starting care at an earlier age was not associated with a decreased risk of ALL. These findings do not support the hypothesis that infrequent contact with peers during early childhood could delay exposure to infectious diseases and increase the risk of ALL.     

Magnetic field exposure from electric appliances and childhood cancer

The effect on childhood cancer of prolonged exposure to 60-H magnetic fields from electric appliances was examined using interview data from a recently completed case-control study. Exposures of children aged 0-14 years whose incident cancers were diagnosed between 1976 and 1983 and who resided in the Denver, Colorado, Standard Metropolitan Statistical Area were compared with those of controls selected by random digit dialing, matched on age, sex, and telephone exchange area. Parents of 252 cases and 222 controls were interviewed at home about the use of electric appliances by the mother during pregnancy (prenatal exposure) and by the child (postnatal exposure). After adjustment for income, prenatal electric blanket exposure was associated with a small increase in the incidence of childhood cancers (odds ratio (OR) = 1.3, 95% confidence interval (CI) 0.7-2.2) that was more pronounced for leukemia (OR = 1.7, 95% CI 0.8-3.6) and brain cancer (OR = 2.5, 95% CI 1.1-5.5). Postnatal exposure to electric blankets was also weakly associated with childhood cancer (OR = 1.5, 95% CI 0.6-3.4), with a larger but imprecise association with acute lymphocytic leukemia (OR = 1.9, 95% CI 0.6-6.5). Water beds and bedside electric clocks were unrelated to childhood cancer incidence. Results are limited by nonresponse and imprecision resulting from the rarity of appliance use, especially for subgroups of cases. Nonetheless, electric blankets, one of the principal sources of prolonged magnetic field exposure, were weakly associated with childhood cancer and warrant a more thorough evaluation.     

Refuelling of vehicles, the use of wood burners and the risk of acute lymphoblastic leukaemia in childhood

It is plausible that exposure of the parents before birth or of the child to sources of benzene increases the risk of childhood acute lymphoblastic leukaemia (ALL). The aim of this analysis was to investigate whether refuelling a vehicle with petrol before birth or burning wood to heat the home before or after the child's birth increased the risk of childhood ALL. Data from 389 cases and 876 frequency-matched controls were analysed using unconditional logistic regression, adjusting for study matching factors and potential confounders. The odds ratio (OR) for the mother ever refuelling a vehicle with petrol for non-occupational purposes before or during the pregnancy was 0.97 [95% confidence interval (CI) 0.69, 1.38]. The OR for the father for this exposure in the year before conception was 0.88 [95% CI 0.52, 1.48]. The OR for use of a closed wood burner to heat the home in the year before or during pregnancy was 1.41 [95% CI 1.02, 1.94] and 1.25 [95% CI 0.92, 1.70] after birth. We found no evidence that non-occupational refuelling a vehicle with petrol in the year before or during pregnancy increased the risk of ALL in the offspring. There was weak evidence that burning wood in a closed burner to heat the home increased the risk, but there was no dose-response relationship and chance could explain the finding.     

Breastfeeding,Other Early Life Exposures and Childhood Leukemia and Lymphoma

Childhood cancer incidence increases and although rare, it is a leading cause of mortality. Leukemia and lymphoma comprise 40% of all cancers in children but little is known of their etiology. In this study, we examined the associations of breastfeeding and other early life exposures with childhood leukemia and lymphoma. A population-based case–control study carried out in 2011–2013 comprised mothers of 190 incidents (2005–2013) of leukemia/lymphoma cases aged 1–19 yr at diagnosis and 384 population-based controls. Interviews based on a computerized structured questionnaire were conducted with the mothers. Multivariate logistic regression models adjusted for potential confounders assessed the association between breastfeeding patterns and childhood leukemia/lymphoma. Ever breastfeeding category was associated with a 64% decreased risk for childhood leukemia/lymphoma lsqb;odds ratio (OR) = 0.36, 95% confidence interval (CI): 0.22, 0.60lrqb; and similar trends, with a dose–response effect, were observed for any breastfeeding (exclusive and/or partial) category for 6, 12, and 18+ mo. Other infant exposures associated with cancer risk were child iron supplementation (OR = 0.39, 95% CI: 0.26, 0.59), pet ownership (OR = 0.50, 95% CI: 0.33, 0.78), paternal smoking (OR = 1.93, 95% CI: 1.18, 3.15), and having older siblings (OR = 1.18, 95% CI: 1.05, 1.33). Breastfeeding—a controllable and modifiable exposure—is inversely associated with risk for childhood leukemia and lymphoma with a dose–response effect.     

A population-based case-control study of occupation and renal cell carcinoma risk in Iowa

A case-control study involving 406 incident cases and 2,434 controls was conducted in Iowa to examine the association between occupational exposures and renal cell carcinoma risk. After adjusting for major confounders, an increased risk was observed for men among mechanics and repairers (odds ratio [OR] 1.9, 95% confidence interval [CI] = 1.2-2.9); assemblers (OR 2.5, 95% CI = 0.8-7.6); automotive dealership and service station employees (OR 1.9, 95% CI = 0.9-3.9); wholesale traders of durable goods (OR 1.5, 95% CI = 0.7-3.2); farm product vendors (OR 4.4, 95% CI = 1.3-15.5); service organization managers (OR 2.2, 95% CI = 1.0-5.1); financial specialists (OR 2.7, 95% CI = 1.0-7.6); sales occupation supervisors (OR 1.8, 95% CI = 1.0-3.3); guards (OR 5.4, 95% CI = 1.4-20.7); and general farm workers (OR 1.9, 95% CI = 1.0-3.7). Among women, an increased risk was found for employees in depository institutions (OR 3.6, 95% CI = 1.1-11.3); colleges and universities (OR 7.6-95% CI = 2.3-25.6); and retail, including those in grocery stores (OR 2.2, 95% CI = 1.0-4.7). Our results indicate that occupational exposures may increase the risk of renal cell carcinoma.     

Childhood asthma in Beijing,China: a population-based case-control study

China is the most populous country in the world. Few studies, however, have been conducted there to investigate the risk factors for childhood asthma. A population-based case-control study was conducted in Shunyi County, People's Republic of China, in January 1999 and March 2001 to investigate the issue. An increased risk of childhood asthma was associated with smoking by relatives in front of the mother while she was pregnant with the child (odds ratio (OR) = 1.3, 95% confidence interval (CI): 1.0, 1.6) and with smoking by relatives in front of the child (OR = 1.4, 95% CI: 1.1, 1.9). The risk increased with the increasing number of smokers and the total minutes of smoking by relatives in front of both the child and the mother while she was pregnant with the child. An increased risk was observed for use of coal for heating (OR = 1.5, 95% CI: 1.1, 1.9). Those who reported using coal for cooking without ventilation also had an increased risk (OR = 2.3, 95% CI: 1.5, 3.5). An increased risk was observed for those who reported having molds or fungi on the ceilings of their houses (OR = 1.8, 95% CI: 1.1, 2.9) or inside the child's room (OR = 1.8, 95% CI: 1.0, 3.2). An increased risk was also found for those having both a dog and a cat as pets (OR = 1.5, 95% CI: 1.0, 2.3) or for finding both cockroaches and rats inside their houses (OR = 1.8, 95% CI: 1.2, 2.8).     

Household solvent exposures and childhood acute lymphoblastic leukemia

OBJECTIVES: This study explored the risk of childhood acute lymphoblastic leukemia (ALL) associated with participation by household members in hobbies or other home projects involving organic solvents. METHODS: Participants in this case-control study were 640 subjects with ALL and 640 matched controls. RESULTS: Childhood ALL was associated with frequent (> 4 times/month) exposure to model building (odds ratio [OR] = 1.9; 95% confidence interval [95% CI] = 0.7, 5.8) and artwork using solvents (OR = 4.1; 95% CI = 1.1, 15.1). We also found elevated risk (OR = 1.7; 95% CI = 1.1, 2.7) among children whose mothers lived in homes painted extensively (> 4 rooms) in the year before the children's birth. CONCLUSIONS: In this exploratory study, substantial participation by household members in some common household activities that involve organic solvents was associated with elevated risks of childhood ALL.     

Parental marijuana use and risk of childhood acute myeloid leukaemia: a report from the Children's Cancer Group (United States and Canada)

The aetiology of childhood acute myeloid leukaemia (AML) is largely unknown. Maternal marijuana use just before, or during pregnancy has been previously associated with childhood AML. This case-control investigation formally tested the hypothesis that parental marijuana use increases the risk of childhood AML in offspring. Incident cases of AML <18 years of age, diagnosed between 1989 and 1993, and registered with the Children's Cancer Group (a paediatric clinical co-operative group), were eligible for inclusion. Control children were selected via random digit dialling and individually matched 1:1 to cases on age, race and residential location, except for rare morphological subtypes that were matched 1:2. Parental telephone interviews were conducted to determine exposure and covariate information. Conditional logistic regression was used to estimate matched odds ratios (OR) and 95% confidence intervals [CI] adjusted for household income, parental education and parental age. The analysis included 517 cases and 610 matched controls. A series of sensitivity analyses examined the potential for recall bias. Ever lifetime use of marijuana by mothers was not associated with childhood AML [OR = 0.89; 95% CI = 0.66, 1.19]. Maternal marijuana use any time during the 3 months before, or during pregnancy was inversely associated with childhood AML [OR = 0.43; 95% CI = 0.23, 0.80]. Paternal use during the same time period was not associated with risk. Assuming a large degree of differential exposure misclassification was present, the corrected ORs ranged between 0.82 and 1.40. The previously reported positive association between maternal marijuana use before or during pregnancy and childhood AML was not confirmed. The decreased ORs observed in this study may be due to recall bias assuming plausibly low values of sensitivity.     

Childhood Injuries in Pakistan: Results from Two Communities

The study aimed at determining the incidence, nature, and extent of childhood injuries in two suburban and rural communities of Pakistan. The findings of the study are based on a cross-sectional survey of 2,292 children aged 1-8 years. Information was sought retrospectively from the primary caregiver on the occurrence of injury that required formal or informal medical consultation during the past three months. The incidence rate of non-fatal injuries that required care outside home for children aged 1-8 years was 19.7 injuries per 100 person (child)-years of exposure [95% confidence interval (CI) 16.41-23.51]: 26.5 injuries per 100 person (child)-years of exposure (95% CI 21.31-32.63) in the suburban area and 12.1 injuries per 100 person (child)-years of exposure (95% CI 8.68-16.66) in the rural area. The most common non-fatal injuries were falls (10.5 fall injuries per 100 person (child)-years of exposure), burns and scalds (3.5 burn injuries per 100 person (child)-years of exposure), and road traffic injuries (RTIs) (2 RTIs per 100 person (child)-years of exposure). One fatality due to drowning was also reported during the study period. The difference among sex was highly significant (p=0.03). Boys (60%) were at a higher risk of injuries compared to girls (40%). The data also revealed that 61% of the injuries took place inside the home. The magnitude of childhood injuries in the two communities was significant compared to the findings of the National Health Survey of Pakistan (1990–1994). The fact that the majority (61%) of the injuries occurred inside the home raises many questions in relation to the household hazards and adequacy of safety and child-proofing measures in these households. There is a need to develop community-based interventions, creating awareness about the consequences of childhood injuries and educating families about preventive measures to reduce the incidence of injuries during early and middle childhood.Key words: Child, Cross-sectional studies, Injuries, Retrospective studies, Pakistan     

Desquamative inflammatory vaginitis: an exploratory case-control study

PURPOSE: To investigate potential risk factors for desquamative inflammatory vaginitis (DIV), a rare but severe form of vaginitis. We are aware of no other controlled studies of DIV. METHODS: We conducted a case control study comparing DIV cases (n = 47), identified from the Wayne State University Vaginitis Clinic, to friend controls. For some variables, cases were also compared to 1432 women participating in a random digit dialing survey. RESULTS: Most cases reported that their last episode of DIV caused at least some pain (76.9%) and worry (73.1%). Cases were more likely than either friend or population controls to report (ORs from population controls) a history of vulvovaginal candidiasis (OR = 4.40, 95% CI 2.24, 8.65), bacterial vaginosis (OR = 25.58, 95% CI 15.91, 41.15), or pelvic inflammatory disease (OR = 16.90, 95% CI 8.26, 34.55); use of oral contraceptives (OR = 4.91, 95% CI 2.11, 11.43); use of hormone replacement therapy (OR = 4.74, 95% CI 2.69, 8.37); and laparoscopic procedures (OR = 22.24, 95% CI 11.46, 42.69). CONCLUSIONS: Future studies should be conducted to explain the association with fertility surgeries, hormone usage, and other urogenital conditions; to clarify the timing of these associations; and to identify other factors related to DIV.     

Measles vaccine effectiveness and risk factors for measles in Dhaka,Bangladesh

OBJECTIVE: To evaluate vaccine effectiveness and to assess risk factors for measles in Dhaka, Bangladesh. METHOD: A case-control study, involving 198 cases with 783 age-matched neighbourhood controls and 120 measles cases with 365 age-matched hospital controls, was conducted in 1995-96 in three large hospitals in Dhaka. FINDINGS: Measles vaccine effectiveness was estimated at 80% (95% confidence interval (CI) = 60-90%) using neighbourhood controls; very similar results were obtained using hospital controls. Visits to a health facility 7-21 days before onset of any symptoms were associated with increased risk of measles compared with neighbourhood (adjusted odds ratio (OR) = 7.0, 95% CI = 4.2-11.6) or hospital (adjusted OR = 1.7, 95% CI = 1.01-2.8) controls. Cases were more likely than controls to come from a household where more than one child lived (adjusted OR = 1.6, 95% CI = 1.1-2.5 versus neighbourhood controls; adjusted OR = 1.8, 95% CI = 1.02-3.0 versus hospital controls). CONCLUSIONS: To improve measles control in urban Dhaka missed immunization opportunities must be reduced in all health care facilities by following WHO guidelines. For measles elimination, more than one dose of vaccine would be required.     

Indoor air pollution from coal combustion and the risk of neural tube defects in a rural population in Shanxi Province, China

The authors evaluated indoor air pollution from coal combustion (IAPCC) as a potential risk factor for neural tube defects (NTDs) in a rural population in Shanxi Province, China. The studied rural population has both high IAPCC exposure and a high prevalence of NTDs. A population-based case-control study was used to identify 610 NTD cases and 837 normal controls between November 2002 and December 2007. Information was collected within 1 week following delivery or pregnancy termination due to prenatal NTD diagnosis. The authors derived an exposure index by integrating a series of IAPCC-related characteristics concerning dwelling and lifestyle. Compared with women with no IAPCC exposure, women with any exposure at all had a 60% increased risk of having a child with an NTD (adjusted odds ratio (OR) = 1.6, 95% confidence interval (CI): 1.1, 2.1). An increased NTD risk was linked to both residential heating (adjusted OR = 1.7, 95% CI: 1.1, 2.4) and cooking (adjusted OR = 1.5, 95% CI: 1.1, 2.1). The risk increased with increases in the exposure index, showing a dose-response trend (P < 0.001). This is the first known study to link IAPCC to NTDs. Additional studies are needed to confirm the link between IAPCC and NTDs.     

Household Exposure to Paint and Petroleum Solvents,Chromosomal Translocations,and the Risk of Childhood Leukemia

Background

Few studies have examined the association between home use of solvents and paint and the risk of childhood leukemia.

Objectives

In this case–control study, we examined whether the use of paint and petroleum solvents at home before birth and in early childhood influenced the risk of leukemia in children.

Methods

We based our analyses on 550 cases of acute lymphoblastic leukemia (ALL), 100 cases of acute myeloid leukemia (AML), and one or two controls per case individually matched for sex, age, Hispanic status, and race. We conducted further analyses by cytogenetic subtype. We used conditional logistic regression techniques to adjust for income.

Results

ALL risk was significantly associated with paint exposure [odds ratio (OR) = 1.65; 95% confidence interval (CI), 1.26–2.15], with a higher risk observed when paint was used postnatally, by a person other than the mother, or frequently. The association was restricted to leukemia with translocations between chromosomes 12 and 21 (OR = 4.16; 95% CI, 1.66–10.4). We found no significant association between solvent use and ALL risk overall (OR = 1.15; 95% CI, 0.87–1.51) or for various cytogenetic subtypes, but we observed a significant association in the 2.0- to 5.9-year age group (OR = 1.55; 95% CI, 1.07–2.25). In contrast, a significant increased risk for AML was associated with solvent (OR = 2.54; 95% CI, 1.19–5.42) but not with paint exposure (OR = 0.64; 95% CI, 0.32–1.25).

Conclusions

The association of ALL risk with paint exposure was strong, consistent with a causal relationship, but further studies are needed to confirm the association of ALL and AML risk with solvent exposure.     

Parental occupational exposure to pesticides and childhood germ-cell tumors

In a recently completed US case-control study (Children's Oncology Group, 1993-2001) with 253 cases and 394 controls, the authors investigated the association between parental occupational exposure to pesticides and risk of childhood germ-cell tumors. Information on occupational pesticide exposure was collected using job-specific module questionnaires and assessed by an experienced industrial hygienist. Odds ratios for childhood germ-cell tumors associated with maternal exposures before pregnancy, during pregnancy, and after the birth of the index child were 1.0 (95% confidence interval (CI): 0.8, 1.4), 1.1 (95% CI: 0.7, 1.6), and 1.3 (95% CI: 0.9, 1.8), respectively. Paternal exposures before pregnancy, during pregnancy, and after the birth of the index child were not related to germ-cell tumors (odds ratios (ORs) were 0.9 (95% CI: 0.7, 1.2), 0.8 (95% CI: 0.5, 1.2), and 0.8 (95% CI: 0.5, 1.3), respectively). When both parents had ever been occupationally exposed to pesticides before the index pregnancy, the odds ratio was 0.8 (95% CI: 0.4, 1.3). Subgroup analyses showed a positive association between maternal exposure to herbicides during the postnatal period and risk of germ-cell tumors in girls (OR = 2.3, 95% CI: 1.0, 5.2) and an inverse association between paternal exposure to pesticides during the index pregnancy and germ-cell tumors in boys (OR = 0.2, 95% CI: 0.1, 1.0). This study did not provide strong evidence supporting a relation between parental pesticide exposure in the workplace and risk of germ-cell tumors among offspring.     

Adult-onset vulvodynia in relation to childhood violence victimization

Researchers have failed to find a consistent association between childhood victimization and vulvodynia, a debilitating, unexplained vulvar pain condition. However, selection bias associated with case ascertainment, and differential reporting bias between clinic-based cases and controls, may explain in part the inconsistent findings. In 2000-2003, the authors identified 125 women experiencing symptoms of vulvar pain consistent with vulvodynia and 125 age- and community-matched controls from the Boston, Massachusetts-area general population. Telephone-administered questionnaires were used to obtain medical, psychiatric, and reproductive histories. Self-administered surveys assessed childhood exposure (age <12 years) to physical and sexual abuse and to poor family support. After author adjustment for socioeconomic position, women with vulvar pain versus controls were 2.6 times more likely to report never/rarely receiving childhood family support, such as comfort, encouragement, and love (95% confidence interval (CI): 1.3, 5.1). Adult-onset vulvodynia was strongly associated with abuse as a child more than a few times physically (odds ratio (OR) = 4.1, 95% CI: 1.7, 10.0) or sexually (OR = 6.5, 95% CI: 1.2, 35.1). When abused women were compared with those with no history of abuse, the association was largely confined to those harmed by a primary family member (OR = 3.6, 95% CI: 1.6, 8.0 for physical abuse; OR = 4.4, 95% CI: 0.9, 22.9 for sexual abuse). Additional population-based studies of clinically confirmed cases of vulvodynia are needed to replicate this association.     

Home remodeling and risk of childhood leukemia

PurposeWe investigated the relationship between the risk of childhood leukemia and home remodeling, a surrogate for indoor chemical exposures.MethodsWe collected information on remodeling activities carried out between birth and diagnosis in homes of 609 acute lymphoblastic leukemia (ALL) cases, 89 acute myeloid leukemia (AML) cases, and 893 matched controls participating in the California Childhood Leukemia Study (1995–2008). We used multivariable logistic regression to estimate the risk of ALL and AML associated with six remodeling activities: construction, painting, recarpeting, reflooring, roofing, and weatherproofing. Models were adjusted for age, sex, Hispanic ethnicity, race, household annual income, and residential mobility.ResultsConstruction in the home between birth and diagnosis was associated with a significant increase in ALL risk (odds ratio [OR]: 1.52, 95% confidence interval [CI]: 1.14–2.02) and a nonsignificant increase in AML risk (OR: 1.75, 95% CI: 0.98–3.15). No other remodeling activities were associated with ALL or AML risk in the main analysis. When stratifying by Hispanic ethnicity, a positive relationship between ALL risk and painting was evident in Hispanic children (OR: 1.47, 95% CI: 1.04–2.07).ConclusionsSpecific home remodeling activities appeared to be associated with increased risk of childhood ALL.     

Physical aggression and social class]

OBJECTIVE: Considering the increase of violence and the scarcity of informations about the relation between social class and victimization by physical aggression, a study was conducted to investigate this association. METHODS: A hospital-based case-control study. Cases and controls were recruited at a hospital, first-aid clinic, from 1/10/93 to 19/1/95. The study included 191 cases and 222 controls selected from among patients with non-violent clinical-surgical complaints, frequency-matched to cases by sex and age. Using a standardized questionnaire applied by trained interviewers, information obtained included social class, skin color, marital status, smoking habits, alcohol consumption and illicit drug use. RESULTS: Adjusting for sex and age, the risk of victimization by physical aggression was significantly higher for the subproletariat, Odds Ratio (OR) 4.20, 95% Confidence Interval (95% CI) 1.99-8.84; single (OR = 2.10) or informal union (OR = 2.62) as marital status (reference group = married); smokers of more than 10 cigarettes/day (OR = 2.75); alcohol consumption (OR = 2.08 for < or = 240 grams/week and OR = 24.05 for > 240 grams/week); and illicit drug users (OR = 3.07). After adjusting for all factors studied a significant risk remained for the subproletariat (OR = 3.28, 95% CI 1.42-7.59); single as marital status (OR = 2.05, 95% CI 1.09-3.88); and alcohol consumption (OR = 2.01, 95% IC 1.07-3.77 for < or = 240 and OR = 15.93, 95% CI 5.09-49.8 for > 240 grams/week) CONCLUSION: Social class is an important factor in the phenomenon of victimization by physical aggression, with the subproletariat deserving special attention in the strategies of intervention regarding this problem.     

儿童白血病的病例对照研究

为了探讨儿童白血病的主要病因,进行1:1配对病例对照研究,结果发现5个危险因素:住家附近有三废污染OR(95% CI)为2.84(1.14~7.10),极低频电磁场暴露OR为2.01(1.18~3.42),儿童X线暴露OR为4.53(1.68~12.21),儿童服用氯霉素OR为3.60(1.62~8.01),服解热镇痛类药物OR为1.93(1.09~3.42);1个保护因素:母亲孕期经常食用鱼、肉类食品OR为0.33(0.18~0.59)。总人群归因危险度表明人群中91%的病例可归因于上述危险因素;X线暴露与氯霉素对儿童白血病的发生有正的交互作用,其相对超额危险度为3.04。