Is there an observational effect? An exploratory study into speed cameras and self-reported offending behaviour.

Fixed and mobile speed cameras are an important element of enforcement initiatives designed to create a strong deterrent effect and improve road safety. Despite the widespread use of the technology and the need to create a strong deterrent effect, research has yet to determine if there is a relationship between levels of exposure to the devices and subsequent self-reported deterrent effects. As a result, licensed motorists (N=536; 51% female) in Queensland (Australia) were recruited to complete a questionnaire that measured exposure to speed cameras and associated offending behaviours. Data were analyzed utilising descriptive, bivariate and multivariate statistics. The key findings that emerged were: the sample reported a higher level of exposure to fixed cameras (even though there are more operational mobile cameras), younger males were most likely to speed and be observant of speed cameras and that perceived certainty of apprehension was the largest reported deterrent force. However, a positive (rather than negative) relationship was found between perceived camera exposure levels and speeding behaviours, which indicates a range of additional factors (both legal and non-legal factors as well as driving exposure levels) influence speed limit non-compliance. Furthermore, multivariate analysis revealed that higher levels of perceptual certainty were associated with general speed compliance and perceptions of the severity and swiftness of sanctions, rather than levels of self-reported camera exposure. This paper is the first to reveal that while motorists prone to speed may be more cognisant of speed camera operations, this in itself does not ensure appropriate behaviour modification.

Dietary fat and postmenopausal breast cancer.

BACKGROUND: Although the results of animal studies and cross-cultural comparisons generally support a role for dietary fat in the etiology of breast cancer, results of analytic epidemiology studies are equivocal. PURPOSE: The association between dietary fat and subsequent breast cancer was examined in a cohort of 34,388 postmenopausal women from Iowa. METHODS: Dietary habits were assessed by a food-frequency questionnaire mailed in January 1986. Through December 31, 1989, 459 incident cases of breast cancer occurred in this cohort. Proportional hazards regression was used to examine the dietary fat-breast cancer association while adjusting for potential confounders. The effects on this association of four analytic approaches to adjustment for energy intake were also considered. RESULTS: After adjustment for known determinants of breast cancer, a modest positive association of total fat intake with risk of breast cancer was seen. Polyunsaturated fat intake was also positively associated with breast cancer (relative risk from lowest to highest intake, 1.0, 1.25, 1.31, and 1.49; P for trend = .052). Different approaches to adjustment for energy intake, however, provided different impressions of the dietary fat-breast cancer association. One method, involving categorization of crude fat intake and inclusion of total energy intake in regression analysis, gave relative risk estimates from low to high fat intake of 1.0, 1.17, 1.25, and 1.38 (P for trend = .18). Another method, based on categorization of fat intake residuals in which the variation in fat due to total energy intake was removed, gave corresponding estimates of 1.0, 1.24, 1.30, and 1.16 (P for trend = .29). The former suggests increasing breast cancer risk with increasing fat intake; the latter suggests no association. CONCLUSIONS: These results are consistent with other cohort studies that have shown a weak association or no association between dietary fat and breast cancer. They are also consistent with studies suggesting that fat intake is a determinant of breast cancer, particularly after accounting for inaccuracies in dietary assessment. The effects of different energy-adjustment methods may account in part for the varying interpretations of four previous cohort studies of dietary fat and breast cancer. IMPLICATIONS: Further work is needed to clarify not only the nature of the dietary fat-breast cancer association, but also the impact of different analytic methods used in the investigation of diet-disease associations.

Association of incident carcinoma of the endometrium with body weight and fat distribution in older women: early findings of the Iowa Women's Health Study.

Previous epidemiological studies have demonstrated that obesity increases endometrial cancer risk two- to 10-fold. To test the hypothesis that abdominal adiposity further increases this relative risk, we conducted a nested case-control study of endometrial cancer incidence in a cohort of 41,873 women ages 55-69 years. Women were recruited by mail and asked to have a friend measure circumferences of several body parts using a tape measure and written instructions. Two-year follow-up for cancer incidence was conducted using a state-wide cancer registry. Compared to random controls (n = 1,274), cases (n = 63) had higher age-adjusted mean values of waist-to-hip circumference ratio (P = 0.10) and trunk-to-limb circumference ratio (waist plus hip circumferences divided by arm plus calf circumferences, P = 0.008). Other anthropometric variables, including current body mass index and current weight, were also greater (P less than 0.001) in cases than controls. After accounting for the association with body mass index, neither the waist-to-hip ratio nor the trunk-to-limb ratio remained associated with endometrial cancer incidence (P greater than 0.40). A 5 kg/m2 increase in body mass index was associated with an adjusted relative risk of endometrial cancer of 1.80 [95% CI = 1.46, 2.22] when other significant risk factors, namely age, education level, extended use of exogenous estrogens, and age at menopause, were taken into account. We conclude that endometrial cancer risk is increased in relation to the amount but not the distribution of adiposity. This is in contrast with several other diseases in which, in addition to overall body mass, the distribution of adiposity is also important.

Associations of abdominal adiposity, fasting insulin, sex hormone binding globulin, and estrone with lipids and lipoproteins in post-menopausal women.

The associations of abdominal adiposity, fasting serum levels of insulin, and sex hormones with blood lipids, lipoproteins, and apolipoproteins A-I and B were studied cross-sectionally in 75 healthy, postmenopausal white women. In univariate analyses, abdominal adiposity (increased waist-to-hip girth ratio) and fasting insulin concentrations were negatively and significantly associated (P less than 0.05) with plasma high density lipoprotein cholesterol (r = -0.47 and -0.38, respectively) and apolipoprotein A-I (r = -0.37 and -0.36), and positively associated with log triglycerides (r = 0.54 and 0.33) and apolipoprotein B (r = 0.43 and 0.22). Sex hormone binding globulin was positively and significantly associated with high density lipoprotein cholesterol (r = 0.32) and negatively associated with log triglyceride (r = -0.45) and apolipoprotein B (r = -0.36). Estrone was positively and significantly associated with high density lipoprotein cholesterol (r = 0.27), apolipoprotein A-I (r = 0.23) and negatively associated with low density lipoprotein cholesterol (r = -0.24) and apolipoprotein B (r = -0.25). Total estradiol, free estradiol, free testosterone, and total testosterone were more weakly associated with the lipid measures. In multivariate analyses, abdominal adiposity remained significantly associated with high density lipoprotein cholesterol, log triglycerides, apolipoproteins A-I and B after adjustment for sex hormone binding globulin, estrone, and insulin concentrations. Insulin remained associated only with apolipoprotein A-I after adjustment for abdominal adiposity, estrone, and sex hormone binding globulin. Sex hormone binding globulin remained marginally associated with log triglyceride (P = 0.07) after adjustment for the remaining three factors. Estrone remained significantly associated with high density lipoprotein cholesterol.(ABSTRACT TRUNCATED AT 250 WORDS)

Central adiposity and increased risk of coronary artery disease mortality in older women.

The relation between central adiposity, measured by the waist/hip circumference ratio (WHR), and 4-year risk of fatal coronary artery disease was examined in a large cohort (n = 32,898) of women aged 55 to 69 years. The age-adjusted relative risk of death from coronary artery disease (115 deaths) was 3.3 for women in the highest tertile of WHR compared to the lowest tertile (95% confidence interval: 2.0, 5.6). After adjustment for age, body mass, smoking, physical activity, estrogen use, marital status, and alcohol intake, the relative risk of coronary death for women in the middle and highest tertiles versus those in the lowest tertile of WHR were 1.3 and 2.8, respectively (P for linear trend < 0.001). Further adjustment for hypertension and diabetes mellitus reduced the estimates slightly to 1.2 and 2.0, but the trend in relative risk remained statistically significant (P = 0.03). In contrast, body mass index showed no independent association with coronary death. Hypertension, diabetes mellitus, cigarette smoking, estrogen nonuse, and being unmarried were significant predictors of greater risk of coronary death in the multivariate model. These results indicate that central adiposity, reflected by an increased WHR, is an important risk factor for death from coronary artery disease in women, most of whom were postmenopausal. The association of central adiposity with risk of coronary death is independent, for the most part, of its association with hypertension and diabetes.

Increased incidence of diabetes mellitus in relation to abdominal adiposity in older women.

The relationship between body fat distribution, measured by the ratio of waist-to-hip circumferences (WHR), and the 2 year incidence of diabetes mellitus was examined in a cohort of 41,837 women aged 55-69 years. The 399 women who reported the new onset of diabetes had a significantly greater mean body mass index (kg/m2) and WHR than non-cases. After adjustment for body mass index (BMI), age and education level using multivariate logistic regression, WHR was a significant independent predictor of diabetes in a dose-response fashion. Cases were 4.6 times (95% CI = 3.8, 5.6) more likely than non-cases to be in the upper tertile of WHR and 2.2 times (95% CI = 1.8, 2.7) more likely to be in the middle tertile. Women in the highest tertiles of both WHR and BMI had a 14.4-fold (95% CI = 9.5, 21.9) higher risk of diabetes than women in the lowest tertiles. These results demonstrate that increased abdominal adiposity is a significant independent risk factor for the development of diabetes mellitus in older women.

Associations of body mass and fat distribution with sex hormone concentrations in postmenopausal women.

The associations of body mass and body fat distribution, as measured by waist-to-hip circumference ratio, with serum concentrations of sex hormones and sex hormone binding globulin were examined in 88 postmenopausal women. Body mass index (BMI) was significantly and negatively associated with sex hormone binding globulin (SHBG) (r = -0.41), luteinizing hormone (LH) (r = -0.40) and follicle stimulating hormone (FSH) (r = -0.38) and was also significantly positively associated with both total and free oestradiol (r = 0.40 and 0.45, respectively). Waist-to-hip circumference ratio was significantly negatively correlated with SHBG (r = -0.53), LH (r = -0.35), and FSH (r = -0.35). After adjustment for BMI and other related factors, waist-to-hip circumference ratio was significantly and negatively associated with SHBG, LH, and FSH, and demonstrated a significant curvilinear relationship with free testosterone. These results suggest that in postmenopausal women, abdominal adiposity is associated with a relatively more androgenic sex hormone profile.

Body fat distribution and self-reported prevalence of hypertension, heart attack, and other heart disease in older women.

The associations of self-reported body mass and fat distribution with self-reported prevalence rates of hypertension, heart attack, and other heart disease were examined in a sample of 40,000 women, aged 55-69 years. Fat distribution was measured by the waist-to-hip circumference ratio (WHR), which had a mean +/- SD of 0.838 +/- 0.085. Prevalence of hypertension was significantly and positively associated with both body mass index (BMI) and waist-to-hip ratio. The prevalence rate ratio for hypertension in the highest versus the lowest tertile of body mass index and waist-to-hip ratio (considered jointly) was 2.7. Prevalence rates of heart attack and other heart disease were significantly and positively associated with waist-to-hip ratio but not with body mass index. The prevalence rate ratios were 2.2 for heart attack and 1.4 for other heart disease in the highest versus the lowest tertile of body mass index and waist-to-hip ratio. Findings were substantiated using multiple logistic regression. These results support the hypothesis that a significant relationship exists between body fat distribution and the occurrence of cardiovascular disease in older women.

Ischaemia of the small intestine in patients with systemic sclerosis: Raynaud's phenomenon or chronic vasculopathy?

We investigated duodenal and gastric mucosal blood flow by endoscopic laser Doppler flowmetry (LDF) in ten patients with systemic sclerosis (SSc) and in ten healthy volunteers. In addition, we tested for the presence of small bowel bacterial overgrowth by jejunal aspiration. Jejunal aspiration and LDF were done consecutively, via a gastroscope, using a flexible catheter and laser Doppler probe. Following these procedures, two duodenal biopsies were obtained for light and electron microscopy. Mean duodenal and gastric blood flow were significantly lower in patients with SSc than in normal subjects (516 flux units vs. 240, 521 vs. 202, both p < 0.001). There was no correlation between age and blood flow in patients or volunteers. Four of the ten patients had evidence of significant bacterial overgrowth on jejunal aspiration (> 10(5) colony-forming units/ml). These findings support the hypothesis that within the small intestine of patients with SSc, factors independent of bacterial overgrowth may be responsible for malabsorption. The observed reduction in small-intestine mucosal blood flow may play an important contributory role. Further studies are required to determine whether this represents reversible or chronic progressive ischaemia, and its effect on nutrient absorption.

Long-term remission from gout associated with fenofibrate therapy.

Short-term studies with fenofibrate, an established treatment for hyperlipidaemia, have shown that its unique side effect of urate lowering is mediated through enhanced renal urate clearance. The long-term effects of fenofibrate on hyperuricaemia and gout have not previously been reported. We report two patients with hyperlipidaemia in association with hyperuricaemia in whom long-term fenofibrate therapy was associated with a sustained reduction in serum urate and lipid levels, together with remission from recurrent attacks of acute gout. The mechanisms involved in these effects and the potential role for fenofibrate in the management of gout are discussed.

Treatment of polymyositis and dermatomyositis.

Polymyositis and dermatomyositis are serious inflammatory muscle disorders which may present life-threatening complications. It is important to recognise and treat the condition in the early stages of the disease. Corticosteroids remain the mainstay of treatment, and their resistance and other forms of immunotherapy are discussed.

Is serum cortisol associated with body fat distribution in postmenopausal women?

The associations of body fat distribution, as measured by waist-to-hip circumference ratio (WHR), with fasting serum cortisol and adrenocorticotropic hormone (ACTH) were examined in 72 healthy postmenopausal women. WHR was not significantly correlated (P greater than 0.05) with either cortisol (r = -0.11) or ACTH (r = 0.10). There were no differences in either mean serum cortisol or ACTH for women in the highest tertile of WHR compared to those in the lowest tertile of WHR, even after adjustment for overall body mass. These results suggest that neither cortisol or ACTH is associated with body fat distribution in postmenopausal women.

Parity-related weight change in women.

Pregnancy is thought to be a major contributor to the excess prevalence of obesity in women compared to men. Pregnancy-related increases in weight are purported to increase the risk that women will develop chronic diseases associated with high body weight. The assertion that pregnancy is associated with permanent weight gain and overweight was examined among 41184 post-menopausal women participating in a population-based study. Women reported lifetime parity, weight at ages 18, 30, 40 and 50 years, and current height. Body weight and body mass index (BMI) increased with age. On average, women gained 11.05 kg, or 0.35 kg per year between the ages of 18 and 50 years. Parity was associated with an increase in body weight from age 18 to 50 years of 0.55 kg per live birth, or 0.09 kg per live birth per year. At each age, women with lifetime parity of one or two live births had lower mean body weight and BMI, and a lower proportion overweight (BMI greater than 27 kg/m2), than either nulliparous women or those with three or more lifetime births. These results indicate a strong association between ageing and weight gain and a weak association between parity and both weight gain and overweight in women.

Shiga toxin-associated hemolytic uremic syndrome: effect of sodium butyrate on sensitivity of human umbilical vein endothelial cells to Shiga toxin.

Escherichia coli O157:H7-related vascular damage such as hemolytic uremic syndrome is believed to require the Shiga-like toxins. This study demonstrated that sodium butyrate sensitized human umbilical vein endothelial cells to Shiga toxin and increased the expression of Shiga toxin receptor, globotriaosylceramide (Gb3), on human umbilical vein endothelial cells.

Characterization of Pseudomonas aeruginosa mutants that are deficient in exotoxin A synthesis and are altered in expression of regA, a positive regulator of exotoxin A.

In Pseudomonas aeruginosa, production of exotoxin A, an ADP-ribosyltransferase, is a complex and highly regulated process. Two positively acting regulatory genes, regA and regB, have been cloned and characterized. To identify additional exotoxin A regulatory genes, we have characterized four N-methyl-N'-nitro-N-nitrosoguanidine-generated mutants of P. aeruginosa PA103 which are deficient in exotoxin A production. These mutants (PA103-8, PA103-15, PA103-16, and PA103-19) do not accumulate intracellular exotoxin A and are not complemented by the cloned toxA or regAB genes. This observation indicates that the lesion(s) in the mutants is probably in an exotoxin A regulatory gene(s) and is not in the genes for secretion of exotoxin A or in the toxA or regAB genes. To assess the effect of the putative regulatory mutations on the toxA and regAB genes, we compared the activity of the toxA and regAB promoters in the mutant and parental strains using plasmids containing the genes for beta-galactosidase or chloramphenicol acetyltransferase under the control of either the toxA or the regAB promoter. The toxA promoter-beta-galactosidase fusion plasmid could not be maintained in PA103-8. beta-Galactosidase expression driven by the toxA promoter was absent in the mutant PA103-19 and occurred at a low level, which was not repressed by iron in mutants PA103-15 and PA103-16. The regAB genes are temporally controlled by two promoters, P1 and P2. In all four mutants, regAB P1 promoter activity was reduced; however, expression under the control of the regAB P2 promoter was normal. These observations suggest the existence of one or more regulatory genes which directly affect expression of both the toxA and the regAB P1 promoters.

Shiga toxin-associated hemolytic uremic syndrome: interleukin-1 beta enhancement of Shiga toxin cytotoxicity toward human vascular endothelial cells in vitro.

Development of hemolytic uremic syndrome (HUS) after infection by Shigella dysenteriae 1 or enterohemorrhagic Escherichia coli has been associated with the production of Shiga toxins (verotoxins). The putative target of Shiga toxins in HUS is the renal microvascular endothelium. This report shows that preincubation of human umbilical vein endothelial cells (HUVEC) with interleukin-1 beta (IL-1 beta) enhances the cytotoxic potency of Shiga toxin toward HUVEC. A preincubation of HUVEC with IL-1 beta is required for sensitization of HUVEC to Shiga toxin. Sensitization of HUVEC to Shiga toxin is IL-1 beta dose dependent. Development of the IL-1 beta response is time dependent, beginning within 2 h of IL-1 beta preincubation and increasing over the next 24 h. That these responses were due to IL-1 beta was demonstrated by heat inactivation of IL-1 beta, by neutralization of IL-1 beta by specific antibody, and by the ability of an IL-1 beta receptor antagonist to inhibit the effect of IL-1 beta. Shiga toxin-related inhibition of HUVEC protein synthesis preceded loss of cell viability. IL-1 beta incubation with HUVEC induced the receptor for Shiga toxin, globotriaosylceramide. Lipopolysaccharide included during IL-1 beta preincubation with HUVEC increased sensitivity to Shiga toxin in an additive manner. We conclude that IL-1 beta may induce Shiga toxin sensitivity in endothelial cells and contribute to the development of HUS.

Detection of early asymptomatic esophageal dysfunction in systemic sclerosis using a new scintigraphic grading method.

OBJECTIVE: To screen patients with systemic sclerosis (SSc) for esophageal disease and to demonstrate a new system of grading dysmotility; to determine the relationship between the symptom of dysphagia and the degree of hypomotility shown by scintigraphy. METHODS: 301 patients with SSc were studied by esophageal scintigraphy using a semisolid orally ingested bolus to detect esophageal dysfunction and gastroesophageal reflux. A new system of grading was used to quantitate the degree of dysfunction, ranging from grade 0 (normal) to grade 4 (severe abnormality). RESULTS: 246 (82%) patients in the study population had evidence of esophageal hypomotility. Gastroesophageal reflux was noted in 83 (28%) patient. The largest number of patients (33%) were found to have grade 2 abnormalities. The number of patients with reflux decreased with increasing severity of grade, from grade 2 to grade 4 (35 to 13%). A retrospective study of the symptoms of 50 of the total study population showed that increasing severity of grade correlated with increasing mean duration of SSc. There was no significant relationship between disease subset and the presence or severity of esophageal hypomotility. 60% of patients in grades 1 and 2 (i.e. with observed dysmotility shown on scintigraphy) had no symptoms of dysphagia. In the more severe grades (scan grades 3 and 4), symptoms of dysphagia correlated with increase in grade. CONCLUSION: Symptoms may be unreliable in judging the presence of extent of esophageal disease in SSc. Esophageal scintigraphy is a useful noninvasive screening test for the detection of asymptomatic disease. The new grading system provides information that rapidly identifies the stage of esophageal disease and gives comparative data for followup and interventional studies.

Incidence of hypertension and stroke in relation to body fat distribution and other risk factors in older women.

The relation between body fat distribution, as measured by the waist-to-hip circumference ratio, and the 2-year incidences of hypertension and stroke were examined in a cohort of 41,837 women aged 55-69 years. Women who developed hypertension were 2.1 (95% confidence interval 1.7-2.6) times more likely to be in the upper tertile of waist-to-hip ratio than those who did not. Adjustment for age, body mass index (kilograms per meter squared), cigarette smoking, physical activity, alcohol intake, and education level reduced this odds ratio to 1.6 (95% confidence interval 1.3-2.1). Women who developed a stroke were also 2.1 (95% confidence interval 1.5-2.9) times more likely to be in the upper tertile of waist-to-hip ratio than those who did not. Adjustment for the same covariates also lowered this odds ratio to 1.6 (95% confidence interval 1.1-2.4). Further adjustment for hypertension and diabetes mellitus reduced the estimated risk of stroke due to elevated waist-to-hip ratio to 1.3 (95% confidence interval 0.8-2.1). Hypertension, diabetes mellitus, and cigarette smoking remained significantly associated with stroke incidence in the multivariate model. These results indicate that abdominal adiposity, as measured by an increased waist-to-hip ratio, increases the risks of hypertension and stroke, even after accounting for overall body mass. The association of abdominal adiposity with risk of stroke is related, in part, to the association of abdominal adiposity with hypertension and diabetes.