A case-control study of traffic risk factors and child pedestrian injury

BACKGROUND: Pedestrian injuries in children constitute an important cause of mortality and morbidity. Specific hazards which contribute to these injuries need to be identified to enable the development of preventive strategies. METHODS: A population-based case-control study was conducted in which 40 aspects of traffic and road environment that contribute to the likelihood of childhood pedestrian injury were examined. The factors of interest were measured at 100 places of injury and 200 control sites between December 1991 and December 1993. RESULTS: The volume of traffic (odds ratio [OR] = 2.16 for an increase of 100 vehicles per hour) in combination with the proportion of vehicles exceeding the speed limit (OR = 1.04) for each 1% increase in average speed, and the presence of footpaths (OR = 11.0) were associated with significant increase in the risk of injury. A graded inverse relationship was present between socioeconomic status and the odds of pedestrian injury. CONCLUSIONS: These findings have obvious implications for public health as features of the physical environment are potentially modifiable.     

A case-control study of risk factors of acute cerebrovascular disease

BACKGROUND: Stroke is the cardiovascular disease which causes the greatest number of deaths in Galicia, mortality, particularly in women, being higher than in the rest of Spain. The aim of this study was to investigate the risk factors of stroke and its importance in Galicia. METHODS: A hospitalary study of cases and controls was performed including 76 patients with stroke and 76 controls individually paired for age, sex, population habitat and date of admission with anamnesis, weight, height and blood pressure, analysis and electrocardiogram being carried out in all. RESULTS: An association was found between the disease and family history of stroke (odds ratio = 3.6, confidence interval 95% = 1.2-13.3), personal history of stroke (17.9; 4.0-79.1), personal history of atrial fibrillation (15.0; 3.3-68.3), high blood pressure (4.5; 1.9-11.6) and ingestion of alcohol greater than or equal to 80 g/day in comparison with abstemious patients adjusted for the effect of high blood pressure (2.5; 1.1-5.7). An association was also observed with serum cholesterol levels greater than or equal to 250 mg/dl (6.46 mmol/l) (3.3; 1.2-8.8, in comparison with cholesterol less than 200 mg/dl). No association was found with the cigarette smoking (1.2; 0.7-2.3). CONCLUSIONS: The results observed for high blood pressure and the ingestion of alcohol regardless of the same are of importance in primary prevention due to being modifiable risk factors. The association with family history of stroke and auricular fibrillation reinforce the needs for primary prevention measures in these subpopulations while having had a stroke or a transitory ischemic attack is the characteristic with the most risk reinforcing the need for secondary prevention measures which have found to be effective. The controls presented abnormally low cholesterol levels that do not reflect those of the population from which they originate, thus existing the possibility that the association observed is spurious.     

A prospective study of reproductive factors and risk of epithelial ovarian cancer

BACKGROUND: Parity and long term use of oral contraceptives have been associated consistently with a decreased risk of ovarian cancer. However, previous reports of the relationship of other reproductive factors (time since first use or last use of oral contraceptives, age at menarche or menopause, age at first birth) with ovarian cancer have been inconsistent. METHODS: The authors studied these relationships in the Nurses' Health Study, a prospective cohort study of 121,700 female registered nurses aged 30-55 years in 1976 when the study began. From 1976 to 1988, 260 cases of confirmed epithelial ovarian cancer occurred among 1.2 million person-years of follow-up. RESULTS: A statistically significant inverse association was observed between parity and ovarian cancer risk (relative risk [RR] = 0.84; 95% confidence interval [CI] = 0.77-0.91 per pregnancy); age at first birth was not associated independently with risk. In age-adjusted analyses, a significant inverse association was noted between long term use of oral contraceptives and ovarian cancer, which was no longer significant after controlling for other ovarian cancer risk factors (RR with > or = 5 years' use: 0.65; 95% CI = 0.40-1.05). After control for duration of use, a weak nonsignificant inverse association was observed with time since first oral contraceptive use and no independent effect of time since last use. Neither age at menarche nor age at menopause was associated significantly with ovarian cancer risk. CONCLUSIONS: In this large prospective study, parity was the only reproductive factor that had a substantial independent association with ovarian cancer. Long term oral contraceptive use also appeared to have an inverse relationship with ovarian cancer, although this association was of borderline significance (P = 0.11) after adjustment for other risk factors.     

A case-control study of dietary intake and other lifestyle risk factors for hyperplastic polyps

BACKGROUND & AIMS: Despite the high prevalence of the hyperplastic polyp, little is known about its etiology. The aim of this study was to assess the relationship between diet and other lifestyle factors and the presence of colorectal hyperplastic polyps. METHODS: Information on diet and other known or suspected risk factors for colorectal cancer or adenoma was collected among 81 subjects with hyperplastic polyps and 480 controls. RESULTS: The multivariate-adjusted odds ratio (OR) for hyperplastic polyps for individuals in the upper vs. the lower quartile was 0.30 (95% confidence interval [CI], 0.10-0.88) for dietary fiber, 0.32 (95% CI, 0.11-0.96) for dietary calcium, 0.90 (95% CI, 0.27-2.95) for total fat, and 2.02 (95% CI, 1.05-3.91) for alcohol consumption. Compared with individuals in the lower category, those in the upper category of body mass index had a higher risk for hyperplastic polyps (OR, 4.50; 95% CI, 1.84-10.97). Cigarette smoking was associated with a higher risk (OR, 1.97; 95% CI, 1.02-3.81 for > 20 pack-years vs. never), whereas an inverse association was seen for use of aspirin and other nonsteroidal anti-inflammatory drugs (OR, 0.29; 95% CI, 0.12-0.67 for once per day or more vs. never). CONCLUSIONS: Hyperplastic polyps share common lifestyle risk factors with colorectal adenomas and carcinomas.     

Dental and cardiac risk factors for infective endocarditis. A population-based, case-control study

BACKGROUND: Although antibiotic prophylaxis against infective endocarditis is recommended, the true risk factors for infective endocarditis are unclear. OBJECTIVE: To quantitate the risk for endocarditis from dental treatment and cardiac abnormalities. DESIGN: Population-based, case-control study. SETTING: 54 hospitals in the Philadelphia area. PATIENTS: Persons with community-acquired infective endocarditis not associated with intravenous drug use were compared with community residents, matched by age, sex, and neighborhood of residence. MEASUREMENTS: Information on demographic characteristics, host risk factors, and dental treatment was obtained from structured telephone interviews, dental records, and medical records. RESULTS: During the preceding 3 months, dental treatment was no more frequent among case-patients than controls (adjusted odds ratio, 0.8 [95% CI, 0.4 to 1.5]). Of 273 case-patients, 104 (38%) knew of previous cardiac lesions compared with 17 controls (6%) (adjusted odds ratio, 16.7 [CI, 7.4 to 37.4]). Case-patients more often had a history of mitral valve prolapse (adjusted odds ratio, 19.4 [CI, 6.4 to 58.4]), congenital heart disease (adjusted odds ratio, 6.7 [CI, 2.3 to 19.4]), cardiac valvular surgery (adjusted odds ratio, 74.6 [CI, 12.5 to 447]), rheumatic fever (adjusted odds ratio, 13.4 [CI, 4.5 to 39.5]), and heart murmur without other known cardiac abnormalities (adjusted odds ratio, 4.2 [CI, 2.0 to 8.9]). Among case-patients with known cardiac lesions--the target of prophylaxis--dental therapy was significantly (P = 0.03) less common than among controls (adjusted odds ratio, 0.2 [CI, 0.04 to 0.7] over 3 months). Few participants received prophylactic antibiotics. CONCLUSIONS: Dental treatment does not seem to be a risk factor for infective endocarditis, even in patients with valvular abnormalities, but cardiac valvular abnormalities are strong risk factors. Few cases of infective endocarditis would be preventable with antibiotic prophylaxis, even with 100% effectiveness assumed. Current policies for prophylaxis should be reconsidered.     

Lifestyle factors and prostate cancer risk: a case-control study in Sweden

We examined associations between lifestyle factors and subsequent risk of prostate cancer in a population-based case-control study. Information on smoking and alcohol habits, socioeconomic factors, marital status, family history, and sexual habits were obtained from a questionnaire and a face-to-face interview with 256 (74.6%) eligible patients and 252 (76.6%) selected controls, frequency matched by age and screened for prostate cancer with negative findings. Unconditional logistic regression was used to estimate the odds ratios (ORs). Risk was elevated among current smokers of cigarettes (OR, 1.8) and current users of hard liquor (OR, 1.4); however, the lack of dose-response trend for both of these exposures argues against a causal association. We found tentative evidence that early first intercourse, a larger number of sexual partners, and other indices of high sexual activity are associated with increased risk. Similarly, adult height, an indicator of nutrition during childhood and adolescence, was weakly positively associated with risk, although larger studies are needed to establish this link. Unmarried men had a lower risk than married men (OR, 0.3), and socioeconomic status did not appear to be strongly associated with prostate cancer. Men with a father who had prostate cancer had a more than 2-fold increased risk of prostate cancer, whereas those with a brother affected had about a 5-folk risk.     

Anthropometric and other risk factors for ovarian cancer in a case-control study

Because it has been suggested that an environmental factor may play a role in the etiology of ovarian cancer, a case-control study was conducted to assess some environmental and other risk factors for ovarian cancer from 1994 to 1996 in northern Kyushu, Japan. We analyzed the data of 89 cases with epithelial ovarian cancer and 323 controls without any cancer or ovarian disorder. After controlling for the effect of potential confounders, the odds ratios of ovarian cancer across increasing quartiles of the heaviest body weight were 1.00, 1.15, 1.71, 2.29 (P = 0.008, test for trend). Significantly increased risks were noted for a history of diabetes mellitus (P < 0.05), and for a family history of ovarian cancer (P < 0.05). Significantly decreased trends for risk were obtained for the number of pregnancies (P < 0.01) and the number of live births (P < 0.001). This study provides additional support for an association between obesity and the risk of ovarian cancer. This relationship may at least partly explain the recent increase in the incidence of ovarian cancer in Japan, although possible contributions of other factors can not be ruled out.     

A case-control questionnaire survey of risk factors for porcine reproductive and respiratory syndrome (PRRS) seropositivity in Danish swine herds

Sixty-eight case herds seropositive to porcine reproductive and respiratory syndrome (PRRS) were compared to 128 seronegative controls in a double-blinded questionnaire survey. The study indicated no increased risk of PRRS seropositivity for herds using artificial insemination with semen from PRRS seropositive AI-stations. Also the herd-size was non-related to the risk of PRRS seropositivity, indicating that air-borne spread of PRRS may not have been a predominant feature in Denmark. Introduction of replacement breeding animals from seropostive breeding- and multiplying herds significantly increased the risk of a herd being PRRS seropositive, as did introduction of 25 kg pigs for feeding. PRRS seropositivity was in the farmers' opinions associated with abortions in sows, early farrowing, high postweaning mortality and low weight gain in fattening pigs. However, the reported frequencies of probelms were relatively low.     

Smoking in pregnancy: a study of psychosocial and reproductive risk factors

In this study relationships between demographic variables and family dynamics of childbearing families in Finland were studied. The sample was 160 urban families expecting their first or second child in the third trimester of pregnancy. One-hundred and eighteen families participated in the study. The Family Dynamics Questionnaire (FDQ) and the Family Dynamics Measure (FDM) were used in this study. Most expectant parents reported their family was well-functioning. Mothers of higher socioeconomic status found more flexibility in their families than mothers of lower socioeconomic status. Fathers in families expecting their first baby reported more mutuality, role reciprocity and more stability than second-time fathers. The findings contribute cues for public health nurses and midwives regarding parity, socioeconomic status and family dynamics to provide more specific family guidance during the transition to parenthood. Realistic information on the changes in family dynamics after childbirth should be given to pregnant parents.     

Intrapartum risk factors for newborn encephalopathy: the Western Australian case-control study

OBJECTIVE: To ascertain antepartum predictors of newborn encephalopathy in term infants. DESIGN: Population based, unmatched case-control study. SETTING: Metropolitan area of Western Australia, June 1993 to September 1995. SUBJECTS: All 164 term infants with moderate or severe newborn encephalopathy; 400 randomly selected controls. MAIN OUTCOME MEASURES: Adjusted odds ratio estimates. RESULTS: The birth prevalence of moderate or severe newborn encephalopathy was 3.8/1000 term live births. The neonatal fatality was 9.1%. The risk of newborn encephalopathy increased with increasing maternal age and decreased with increasing parity. There was an increased risk associated with having a mother who was unemployed (odds ratio 3.60), an unskilled manual worker (3.84), or a housewife (2.48). Other risk factors from before conception were not having private health insurance (3.46), a family history of seizures (2.55), a family history of neurological disease (2.73), and infertility treatment (4.43). Risk factors during pregnancy were maternal thyroid disease (9.7), severe pre-eclampsia (6.30), moderate or severe bleeding (3.57), a clinically diagnosed viral illness (2.97), not having drunk alcohol (2.91); and placenta described at delivery as abnormal (2.07). Factors related to the baby were birth weight adjusted for gestational age between the third and ninth centile (4.37) or below the third centile (38.23). The risk relation with gestational age was J shaped with 38 and 39 weeks having the lowest risk. CONCLUSIONS: The causes of newborn encephalopathy are heterogeneous and many of the causal pathways start before birth.     

A case-control study of occupational and environmental risk factors for Parkinson's disease in the Emilia-Romagna region of Italy

A questionnaire-based case-control study was carried out on 86 patients with neurologist-confirmed idiopathic Parkinson's disease (PD) and 86 controls similar in sex and age. The control group was recruited in outpatient specialist centers of the same University Hospital (glaucoma, psoriasis vulgaris, essential arterial hypertension and renal diseases). Exposure was defined as occupational or residential contact with a given factor for at least 10 consecutive years prior to the onset of PD. Smoking habits were defined by exclusion of those subjects who never smoked. The following risk factors were identified: cranial trauma (OR: 2.88; 95% CI: 0.98-8.49), well water use (OR: 2.78; 95% CI: 1.46-5.28) and occupational exposure to industrial chemicals (OR: 2.13; 95% CI: 1.16-3.91). Among industrial chemicals, only organic solvents were identified as significant risk factors for PD (O.R. : 2.78, 95% C.I. : 1.23-6.26). Whereas no exposure to neurotoxic metals occurred among controls, making the assessment of the O.R. impossible, exposure pesticides and herbicides was similar in the two groups (O.R. : 1.15; 95% C. : 0.56-2-36). Smoking habits was negatively associated with PD (OR: 0.41; 95% CI: 0.22-0.75), confirming the "protective" role of tobacco smoking suggested by many studies. As a whole, these results support the role of environmental factors in the etiology of PD.     

Risk factors for rifampin-monoresistant tuberculosis: A case-control study

Rifampin is the cornerstone of short-course chemotherapy for the treatment of tuberculosis (TB). Rifampin monoresistance (RMR) is less common than resistance to isoniazid alone or in combination with other antituberculous medications. We conducted a retrospective case-control study to identify risk factors for RMR-TB. Complete records for 21 of a total of 26 RMR patients from 1990 to 1997 were available for review, and were compared with those of 48 patients with drug-susceptible TB, controlling for year of diagnosis. Cases more frequently had a history of TB than did controls (61% versus 22%, p < 0.01), and were more often human immunodeficiency virus (HIV) positive (81% versus 46%, p = 0.02). With control for HIV status, cases were more likely to have extrapulmonary involvement (47.6% versus 11.6%, p = 0.05). Four cases (19%) and one control (2. 1%) died (p = 0.02) during hospitalization. Cases more often had a history of incarceration (71.4% versus 37.5%, p = 0.09). Among the 13 cases with a history of TB, five had evidence of malabsorption (vomiting and/or diarrhea), versus none of the 11 controls with prior TB. These data support the hypothesis that RMR is seen primarily in individuals with a history of TB and who are HIV positive. Cases were frequently noncompliant with previous treatment for TB, had a history of incarceration, and had poor outcomes.     

Some occupational exposures as risk factors for malignant lymphomas

BACKGROUND: Malignant lymphomas (Hodgkin disease [HD] and non-Hodgkin lymphoma [NHL]) have been subject to several epidemiologic studies and found to be associated with various environmental exposures, especially solvents, wood, and phenoxy herbicides. METHODS: Various determinants for HD and NHL were evaluated in a case-referent study encompassing 31 cases of HD, 93 cases of NHL, and 204 referents, all alive. Information on these determinants, mainly occupational exposures, was obtained by mailed questionnaires. RESULTS: Crude odds ratios were increased for various occupational exposures, i.e., exposures to solvents, pesticides, metal fumes, welding, and fresh wood, and nursing. Further analyses based on logistic regression indicated exposure to phenoxy herbicides and fresh wood among sawmill workers, lumberjacks, and paper pulp workers to be significant risk factors for HD. Welding, working as a lumberjack, nursing, and ex-smoking were associated with a significantly increased risk for NHL. Radiographic examinations were negatively associated with HD, as was office work for NHL. CONCLUSIONS: The results were mainly in agreement with the findings of earlier studies, but diverging associations also appeared.     

A case-control study of the relationship between dietary factors and risk of lung cancer in women of Shenyang, China

A 1:1 case-control study of lung cancer incidence among women in Shenyang was conducted to explore the relationship between diet and the risk of lung cancer, with emphasis on the potential effects of a list of specific dietary constituents on modifying lung cancer risks. Dietary information on 290 cases and population-matched controls was obtained by personal interviews. Multiple logistic regression models were used for the statistical analysis and summarization of the data. A significant difference was found between cases and controls with respect to intake of beta-carotene, vitamin C and fibers, all of which reduced the risk for lung cancer in a dose-dependent manner; yielding calculated odds ratio (OR) of 0.84, 0.75, and 0.46, respectively. The apparent effects of these nutrients persisted after adjusting for cigarette smoking;suggesting that they may function as protective factors to reduce the risk for lung cancer in Chinese women.     

Long-term impact of reproductive factors on cancer risk

In the program ODS we provide a methodology for quickly ordering random clones into a physical map. The process of ordering individual clones with respect to their position along a chromosome is based on the similarity of binary signatures assigned to each clone. This binary signature is obtained by hybridizing each clone to a panel of oligonucleotide probes. By using the fact that the amount of overlap between any two clones is reflected in the similarity of their binary signatures, it is possible to reconstruct a chromosome by minimizing the sum of linking distances between an ordered sequence of clones. Unlike other programs for physical mapping, ODS is very general in the types of data that can be utilized for chromosome reconstruction. Any trait that can be scored in a presence--absence manner, such as hybridized synthetic oligonucleotides, restriction endonuclease recognition sites or single copy landmarks, can be used for analysis. Furthermore, the computational requirements for the construction of large physical maps can be measured in a matter of hours on work-stations such as the VAX2000.     

Malignant melanoma risk factors by anatomic site: a case-control study and polychotomous logistic regression analysis

This population-based case-control study systematically examined reported malignant melanoma risk factors by anatomic site. Study subjects consisted of 548 invasive melanoma cases diagnosed in Connecticut during 1987-1989 and 494 randomly selected controls. Multivariate polychotomous logistic regression was used to determine whether risk factors differed across anatomic sites. Risk factors examined included demographic and pigmentary characteristics, sun exposure-related factors, anatomic site-specific sunburn, recreational water activity clothing habits and number of nevi. A pattern of site-specificity was observed for sunburn. A history of sunburn at an anatomic site was specifically related to the development of malignant melanoma at that site more so than at other sites. This site-specificity was consistent with a direct role for intense, intermittent sun exposure in the development of melanoma. Age and gender were the only risk factors that differed significantly in effect across anatomic sites. The age difference was explained by differences in histologic subtype across sites. The gender difference could not be explained by sex differences in anatomic site-specific sunburns or in recreational water activity clothing habits. Alternative explanations include sex differences in behavioral patterns of sun exposure that we did not measure and as yet unelucidated differences in susceptibility to melanoma according to sex and anatomic site.     

Menstrual and reproductive factors and risk of breast cancer in Asian-Americans

We conducted a population-based case-control study of breast cancer among Chinese-, Japanese- and Filipino-American women in Los Angeles County Metropolitan Statistical Area (MSA), San Francisco-Oakland MSA and Oahu, Hawaii. One objective of the study was to quantify breast cancer risks in relation to menstrual and reproductive histories in migrant and US-born Asian-Americans and to establish whether the gradient of risk in Asian-Americans can be explained by these factors. Using a common study design and questionnaire in the three study areas, we successfully conducted in-person interviews with 597 Asian-American women diagnosed with incident, primary breast cancer during the period 1983-87 (70% of those eligible) and 966 population-based controls (75% of those eligible). Controls were matched to cases on age, ethnicity and area of residence. In the present analysis, which included 492 cases and 768 controls, we observed a statistically non-significant 4% reduction in risk of breast cancer with each year delay in onset of menstruation. Independent of age at menarche risk of breast cancer was lower (odds ratio; OR=0.77) among women with menstrual cycles greater than 29 days. Parous Asian-American women showed a significantly lower risk of breast cancer then nulliparous women (OR=0.54). An increasing number of livebirths and a decreasing age at first livebirth were both associated with a lower risk of breast cancer, although the effect of number of livebirths was no longer significant after adjustment for age at first livebirth. Women with a pregnancy (spontaneous or induced abortions) but no livebirth had a statistically non-significant increased risk (OR=1.84), but there was no evidence that one type of abortion was particularly harmful. A positive history of breastfeeding was associated with non-significantly lower risk of breast cancer (OR=.78). There are several notable differences in the menstrual and reproductive factors between Asian-Americans in this study and published data on US whites. US-born Asian Americans had an average age at menarche of 12.12 years-no older than has been found in comparable studies of US whites, but 1.4 years earlier than Asian women who migrated to the US. Asian-American women, particularly those born in the US and those who migrated before age 36, also had a later age at first birth and fewer livebirths than US whites. A slightly higher proportion of Asian-American women breastfed, compared with US whites. The duration of breastfeeding was similar in US-born Asians and US whites, but was longer in Asian migrants, especially those who migrated at a later age. Menstrual and reproductive factors in Asian-American women are consistent with their breast cancer rates being at least as high as in US whites, and they are. However, the effects of these menstrual and reproductive factors were small and the ORs for migration variables changed only slightly after adjustment for these menstrual and reproductive factors. These results suggest that the lower rates of breast cancer in Asians must be largely as a result of other environmental/lifestyle factors.     

Dietary habits, reproductive and menstrual factors and risk of dysmenorrhoea

In order to analyze risk factors for dysmenorrhoea, we conducted a case-control study. Cases were 106 women (median age 27 years) with moderate or severe dysmenorrhoea lasting 12 months or more. Controls were 145 women (median age 26 years) without dysmenorrhoea, admitted for routine gynecological examination at the outpatient gynecological services of the same clinic where cases had been identified. In comparison with women reporting short menstrual cycles (every 25 days or less) the relative risk (RR) of dysmenorrhoea was 2.0 and 2.6, respectively, in those reporting their menstrual cycles of 26-30 days and of 31 days or more, and the RR was 3.6 (95% confidence interval (CI): 1.0-13.4) for women reporting totally irregular menstrual cycles. The estimated RRs were, in comparison with women reporting menstrual flows lasting 4 days or less, respectively 2.2 and 1.9 in those reporting menstrual flows lasting 5 and 6 days or more. Fourty-four (58%) cases but only seven (5%) controls reported heavy menstrual flows (RR in comparison with women reporting slight or normal menstrual flow 12.6, 95% CI: 5.0-32.1). As regards dietary factors, no associations emerged between the various food items, with the exception of cheese and eggs, which tended to be more frequently consumed by cases than controls. The results of this study suggest that the risk of dysmenorrhoea is higher in women with irregular, long and heavy menstrual flows. No association emerged between reproductive history and dysmenorrhoea. Likewise, no clear relationship emerged between intake of several dietary factors and risk dysmenorrhoea.     

Dermatological indicators of coronary risk: a case-control study

Varicella pneumonia is the most common complication of adult varicella. Symptoms may be severe and the mortality rate high in patients who are immunodeficient or pregnant. Symptoms may be mild and progression more favorable in adults previously in good health. We report two cases of varicella infection complicated by severe pulmonary involvement in adult patients who were previously healthy. Case 1 was a 36-year-old male who 6 days after developing varicella was clinically observed to have dyspnea and hemopytsis. He died of acute respiratory failure on the following day. Case 2 was a 28-year-old male whose respiratory symptoms started the third day after developing varicella. These symptoms were relieved by treatment with acyclovir and gammaglobulin. Careful observation is and an early treatment of varicella should be undertaken not only for patients with suppressed cellular immunity, but also for healthy adults, to prevent severe complications.