Susan J. Bondy

Chiropractic Manipulation and Stroke A Population-Based Case-Control Study

Background and Purpose Several reports have linked chiropractic manipulation of the neck to dissection or occlusion of the vertebral artery. However, previous studies linking such strokes to neck manipulation consist primarily of uncontrolled case series. We designed a population-based nested case-control study to test the association. Methods Hospitalization records were used to identify vertebrobasilar accidents (VBAs) in Ontario, Canada, during 1993–1998. Each of 582 cases was age and sex matched to 4 controls from the Ontario population with no history of stroke at the event date. Public health insurance billing records were used to document use of chiropractic services before the event date. Results Results for those aged <45 years showed VBA cases to be 5 times more likely than controls to have visited a chiropractor within 1 week of the VBA (95% CI from bootstrapping, 1.32 to 43.87). Additionally, in the younger age group, cases were 5 times as likely to have had ≥3 visits with a cervical diagnosis in the month before the case’s VBA date (95% CI from bootstrapping, 1.34 to 18.57). No significant associations were found for those aged ≥45 years. Conclusions While our analysis is consistent with a positive association in young adults, potential sources of bias are also discussed. The rarity of VBAs makes this association difficult to study despite high volumes of chiropractic treatment. Because of the popularity of spinal manipulation, high-quality research on both its risks and benefits is recommended.

Risk of vertebrobasilar stroke and chiropractic care: results of a population-based case-control and case-crossover study.

Study Design. Population-based, case-control and case-crossover study. Objective. To investigate associations between chiropractic visits and vertebrobasilar artery (VBA) stroke and to contrast this with primary care physician (PCP) visits and VBA stroke. Summary of Background Data. Chiropractic care is popular for neck pain and headache, but may increase the risk for VBA dissection and stroke. Neck pain and headache are common symptoms of VBA dissection, which commonly precedes VBA stroke. Methods. Cases included eligible incident VBA strokes admitted to Ontario hospitals from April 1, 1993 to March 31, 2002. Four controls were age and gender matched to each case. Case and control exposures to chiropractors and PCPs were determined from health billing records in the year before the stroke date. In the case-crossover analysis, cases acted as their own controls. Results. There were 818 VBA strokes hospitalized in a population of more than 100 million person-years. In those aged <45 years, cases were about three times more likely to see a chiropractor or a PCP before their stroke than controls. Results were similar in the case control and case crossover analyses. There was no increased association between chiropractic visits and VBA stroke in those older than 45 years. Positive associations were found between PCP visits and VBA stroke in all age groups. Practitioner visits billed for headache and neck complaints were highly associated with subsequent VBA stroke. Conclusion. VBA stroke is a very rare event in the population. The increased risks of VBA stroke associated with chiropractic and PCP visits is likely due to patients with headache and neck pain from VBA dissection seeking care before their stroke. We found no evidence of excess risk of VBA stroke associated chiropractic care compared to primary care.

The effects of introducing or lowering legal per se blood alcohol limits for driving: an international review

In this review evidence on the impact of introducing or lowering legal blood alcohol limits on traffic safety measures is examined. There is substantial variability in the types and rigour of methods used to evaluate these legislative measures, and thus not surprisingly there is variability in the results observed. In most but not all cases where an evaluation of an introduced or lowered legal limit has been conducted, some beneficial effect on traffic safety measures has been reported. These effects are in some cases relatively small, and in other cases may be temporary. In some jurisdictions, lasting reductions in collision rates have been reported. Available evidence suggests that where beneficial effects are observed they are due to general deterrence, and not restricted only to drivers at blood alcohol concentrations (BAC) specifically affected by the legal change.

Risk of Vertebrobasilar Stroke and Chiropractic Care : Results of a Population-Based Case-Control and Case-Crossover Study

STUDY DESIGN Population-based, case-control and case-crossover study. OBJECTIVE To investigate associations between chiropractic visits and vertebrobasilar artery (VBA) stroke and to contrast this with primary care physician (PCP) visits and VBA stroke. SUMMARY OF BACKGROUND DATA Chiropractic care is popular for neck pain and headache, but may increase the risk for VBA dissection and stroke. Neck pain and headache are common symptoms of VBA dissection, which commonly precedes VBA stroke. METHODS Cases included eligible incident VBA strokes admitted to Ontario hospitals from April 1, 1993 to March 31, 2002. Four controls were age and gender matched to each case. Case and control exposures to chiropractors and PCPs were determined from health billing records in the year before the stroke date. In the case-crossover analysis, cases acted as their own controls. RESULTS There were 818 VBA strokes hospitalized in a population of more than 100 million person-years. In those aged <45 years, cases were about three times more likely to see a chiropractor or a PCP before their stroke than controls. Results were similar in the case control and case crossover analyses. There was no increased association between chiropractic visits and VBA stroke in those older than 45 years. Positive associations were found between PCP visits and VBA stroke in all age groups. Practitioner visits billed for headache and neck complaints were highly associated with subsequent VBA stroke. CONCLUSION VBA stroke is a very rare event in the population. The increased risks of VBA stroke associated with chiropractic and PCP visits is likely due to patients with headache and neck pain from VBA dissection seeking care before their stroke. We found no evidence of excess risk of VBA stroke associated chiropractic care compared to primary care.

Intimate partner violence is associated with incident HIV infection in women in Uganda

Objectives:To quantify the association between intimate partner violence (IPV) and incident HIV infection in women in the Rakai Community Cohort Study between 2000 and 2009. Design and methods:Data were from the Rakai Community Cohort Study annual surveys between 2000 and 2009. Longitudinal data analysis was used to estimate the adjusted incidence rate ratio (IRR) of incident HIV associated with IPV in sexually active women aged 15–49 years, using a multivariable Poisson regression model with random effects. The population attributable fraction was calculated. Putative mediators were assessed using Baron and Kennys criteria and the Sobel–Goodman test. Results:Women who had ever experienced IPV had an adjusted IRR of incident HIV infection of 1.55 (95% CI 1.25–1.94, P = 0.000), compared with women who had never experienced IPV. Risk of HIV infection tended to be greater for longer duration of IPV exposure and for women exposed to more severe and more frequent IPV. The adjusted population attributable fraction of incident HIV attributable to IPV was 22.2% (95% CI 12.5–30.4). There was no evidence that either condom use or number of sex partners in the past year mediated the relationship between IPV and HIV. Conclusion:IPV is associated with incident HIV infection in a population-based cohort in Uganda, although the adjusted population attributable fraction is modest. The prevention of IPV should be a public health priority, and could contribute to HIV prevention.

Smoking in the home: changing attitudes and current practices.

OBJECTIVES Trends in attitudes and current practices concerning smoking in the home were examined. METHODS Data from population-based surveys of adults in Ontario, Canada, were analyzed. RESULTS Between 1992 and 1996, the percentage of respondents who agreed that parents spending time at home with small children should not smoke increased from 51% to 70%. In 1996, 34% of the homes surveyed were smoke-free. Smoke-free homes were associated with nonsmoking respondents and with the presence of children and no daily smokers in the home. Only 20% of homes with children and any daily smokers were smoke-free. CONCLUSIONS Efforts are needed to assist parents in reducing childrens exposure to environmental tobacco smoke in the home.

Origin and use of the 100 cigarette criterion in tobacco surveys

Truly global standards and definitions will likely never exist for tobacco control surveillance. One difference across definitions of smoking status is whether or not a lifetime consumption of 100 cigarettes is a necessary criterion for ever and current smoking. Frequently asked questions about this measure demonstrate a need for information on its development and appropriateness in different settings. This commentary attempts to assemble information on the origin and adoption of this measure and provide some critical commentary on its usefulness. The question has been traced to Canadian and American mortality cohort studies from the mid-1950s. From there it has spread to inconsistent use in many settings. To our knowledge, it was not originally (or since) empirically defined as a threshold of exposure related to health consequences or future smoking risk when used in youth. Anecdotal evidence over several decades, however, shows the question has pragmatic utility in self-report data collection. It is a useful, if somewhat arbitrary, screener for “never regular” tobacco use among adults, where never smoking needs to be defined in data collection. Use of the criterion may lower prevalence estimates somewhat. Definitions must always be considered when creating time-trends or international comparisons. There are also circumstances where it is inappropriate to exclude individuals who do not meet this criterion from further data collection, or reports. For research in youth, the criterion typically should be used only with more detailed information about experimentation, but it may be a useful additional indicator of established smoking.

Determination of Lifetime Injury Mortality Risk in Canada in 2002 by Drinking Amount per Occasion and Number of Occasions

Injury is the leading cause of alcohol-attributable mortality in Canada. Risk is determined by amount consumed per occasion and accumulates across drinking episodes. The authors estimated alcohol-attributable injury mortality in Canada for 2002 by combining the absolute risk of injury unrelated to alcohol with relative risks that were specific to gender and consumption per occasion, while taking into account lifetime number of drinking occasions. The absolute risk increased as number of drinking occasions and number of drinks per occasion increased. The absolute risk remained relatively low at fewer than 2 drinking occasions per month, regardless of number of drinks. Absolute risk levels reached 1 in 1,000 at 5 or more drinks once per month for men and at 5-7 drinks once per month for women. The probability of mortality was 1 in 100 for all levels of consumption above 3 drinks 3 times per week for men and above 5 drinks 3 times per week for women. No safe level of consumption is recommended based on these results, although risk is much lower for consuming 3 standard drinks or less fewer than 3 times per week. Absolute risk reflects long-term effects of drinking patterns and is important for risk-communication and alcohol-control policy.

Suicidality, depression, and mental health service use in Canada

Objective: To determine the magnitude of depression and suicidal populations, the overlap between these populations, and the associated patterns of mental health service use. Method: We examined depression, suicidality (ideation and nonfatal behaviours), and the mental health service use of participants in the Canadian Community Health Survey Cycle 1.2: Mental Health and Well-Being. The sample comprised 36 984 household members aged 15 years or over. Results: Approximately 4% to 5% of the population suffered from a major depression or suicidality. About 2 of 3 of those who were suicidal did not suffer from depression, and over 70% of those with depression did not report suicidality. Persons with depression and suicidality or depression (but no suicidality) were the 2 groups most likely to report ambulatory mental health contacts, and the provider groups contacted most often included physicians. The use of provider groups was considerably lower for those who were suicidal (but had no depression). Whereas the latter were more likely to report contacts than not, suicidality, in and of itself, did not exert a strong effect on contact with any particular provider group. For those who were suicidal (but who had no depression), less than 1 in 3 reported any mental health service contact, including an inpatient mental health stay. Conclusions: The lack of contact by those who are suicidal (but who have no depression) is provocative, given that almost 2 of 3 of the suicidal subjects had no depression. Detrimental outcomes such as depression may develop without effective early interventions and uptake by a sufficient supply of appropriately trained and financially accessible personnel.

Gender differences in stroke care decision-making

Background:Women are less likely than men to receive some stroke care interventions. It is not known whether gender differences in patient preferences explain some of the observed variations in stroke care delivery. Methods:Outpatients with and without a history of cerebrovascular disease were recruited from stroke, vascular, and general internal medicine ambulatory clinics between September 2002 and October 2003. Self-administered surveys described hypothetical scenarios, and participants were asked if they would accept therapy with thrombolysis for acute ischemic stroke or carotid endarterectomy for secondary stroke prevention. The surveys also included questions on sociodemographic factors and decision-making preferences. Results:A total of 586 patients (45% women) completed the survey. Women were less likely than men to accept thrombolysis (79% vs. 86%, P = 0.014), even after adjustment for other factors (adjusted odds ratio [OR] 0.58, 95% confidence interval [CI] 0.37–0.92). Women and men were equally likely to accept carotid endarterectomy (82% vs. 84%, P = 0.502), even after adjustment for other factors (adjusted OR 0.94, 95% CI 0.58– 1.53). Women were less confident in their decisions, were more risk averse, and would have preferred more information to assist them in their decision-making. Conclusions:No gender differences were found in patient preferences for carotid surgery. However, we observed gender differences in patient preferences for thrombolysis and in general attitudes toward stroke care decision-making. Health care providers should be aware that, compared with men, women may be more concerned about risks and may require more information before they make a decision.