Nancy Yu

The rising prevalence and changing age distribution of multiple sclerosis in Manitoba

Objective: Several studies suggest an increasing prevalence of multiple sclerosis (MS) in Canada. We aimed to validate a case definition for MS using administrative health insurance data, and to describe the incidence and prevalence of MS in Manitoba, Canada. Methods: We used provincial administrative claims data to identify persons with demyelinating disease using International Classification of Diseases 9/10 codes and prescription claims. To validate the case definition, questionnaires were mailed to 2,000 randomly selected persons with an encounter for demyelinating disease, requesting permission for medical records review. We used diagnoses abstracted from medical records as the gold standard to evaluate candidate case definitions using administrative data. Results: From 1984 to 1997, cases of MS using claims data were defined as persons with ≥7 medical contacts for MS. From 1998 onward, cases were defined as persons with ≥3 medical contacts. As compared to medical records, this definition had a positive predictive value of 80.5% and negative predictive value of 75.5%. From 1998 to 2006, the average age- and sex-adjusted annual incidence of MS per 100,000 population was 11.4 (95% confidence interval [CI] 10.7–12.0). The age-adjusted prevalence of MS per 100,000 population increased from 32.6 (95% CI 29.4–35.8) in 1984 to 226.7 (95% CI 218.1–235.3) in 2006, with the peak prevalence shifting to older age groups. Conclusion: The prevalence of multiple sclerosis (MS) in Manitoba is among the highest in the world. The rising prevalence with minimally changing incidence suggests improving survival. This study supports the use of administrative data to develop case definitions and further define the epidemiology of MS.

The relationship between inflammatory bowel disease and socioeconomic variables

Abstract OBJECTIVES: Inflammatory bowel diseases (IBD) are chronic diseases associated with considerable morbidity. This morbidity may have an impact on the ability of patients to remain employed, on their marital status, and on their ability to complete a course of higher education. It has long been held that IBD patients are of a higher socioeconomic status and more educated than the general population. Our aim was to determine the relationship between IBD and employment, income, disability, education, and marital status in two population-based data sets based in the province of Manitoba, Canada. METHODS: Two studies are reported here. In study A, we surveyed persons with IBD, using the population-based University of Manitoba IBD Database, created in 1995–1996. We compared these IBD patients to the general population with respect to employment, education, and marital status using data from the 1996 National Population Health Survey. IBD patients were queried as to their socioeconomic status as of the time of diagnosis and also at the time of the survey (1995–1996). In study B, we used a database that linked health care and census variables to determine differences in employment, income, occupation, and marital status among individuals who met the administrative definition of IBD (created in forming the University of Manitoba IBD Database, based on ICD-9-CM codes 555 for Crohn’s disease and 556 for ulcerative colitis) compared with the rest of working-age population. RESULTS: In study A we found that, compared with the general population, patients with IBD were more likely to be unemployed. Crohn’s disease appeared to affect employment more than ulcerative colitis. IBD patients, however, had a low rate of reporting themselves as disabled (1.3%). Among those married when diagnosed with IBD, approximately 10% of men and up to 20% of women were no longer married 5 yr later. More patients with IBD were married in 1995 compared with the general population; however, more were also divorced. Fewer patients with IBD achieved postsecondary education. In study B, we found that individuals with IBD were twice as likely to be out of the labor force as were controls. Sedentary occupations were twice as likely to be associated with IBD. The income, education level, and marital status of IBD patients were not significantly different from those of controls. CONCLUSIONS: Individuals with IBD at some time in the course of their illness are more likely not to be working than are those in the general population. Based on employment status and job classification, as well as income and education, IBD patients are not of a higher socioeconomic status as previously reported. IBD patients are at least as likely as the general population to be married.

Effect of comorbidity on mortality in multiple sclerosis

Objective: We aimed to compare survival in the multiple sclerosis (MS) population with a matched cohort from the general population, and to evaluate the association of comorbidity with survival in both populations. Methods: Using population-based administrative data, we identified 5,797 persons with MS and 28,807 controls matched on sex, year of birth, and region. We estimated annual mortality rates. Using Cox proportional hazards regression, we evaluated the association between comorbidity status and mortality, stratifying by birth cohort, and adjusting for sex, socioeconomic status, and region. We compared causes of death between populations. Results: Median survival from birth in the MS population was 75.9 years vs 83.4 years in the matched population. MS was associated with a 2-fold increased risk of death (adjusted hazard ratio 2.40; 95% confidence interval: 2.24–2.58). Several comorbidities were associated with increased hazard of death in both populations, including diabetes, ischemic heart disease, depression, anxiety, and chronic lung disease. The magnitude of the associations of mortality with chronic lung disease, diabetes, hypertension, and ischemic heart disease was lower in the MS population than the matched population. The most common causes of death in the MS population were diseases of the nervous system and diseases of the circulatory system. Mortality rates due to infectious diseases and diseases of the respiratory system were higher in the MS population. Conclusion: In the MS population, survival remained shorter than expected. Within the MS population, comorbidity was associated with increased mortality risk. However, comorbidity did not preferentially increase mortality risk in the MS population as compared with controls.

Nutritional and health benefits of pulses.

Pulses (beans, peas, and lentils) have been consumed for at least 10 000 years and are among the most extensively used foods in the world. A wide variety of pulses can be grown globally, making them important both economically as well as nutritionally. Pulses provide protein and fibre, as well as a significant source of vitamins and minerals, such as iron, zinc, folate, and magnesium, and consuming half a cup of beans or peas per day can enhance diet quality by increasing intakes of these nutrients. In addition, the phytochemicals, saponins, and tannins found in pulses possess antioxidant and anti-carcinogenic effects, indicating that pulses may have significant anti-cancer effects. Pulse consumption also improves serum lipid profiles and positively affects several other cardiovascular disease risk factors, such as blood pressure, platelet activity, and inflammation. Pulses are high in fibre and have a low glycemic index, making them particularly beneficial to people with diabetes by assisting in maintaining healthy blood glucose and insulin levels. Emerging research examining the effect of pulse components on HIV and consumption patterns with aging populations indicates that pulses may have further effects on health. In conclusion, including pulses in the diet is a healthy way to meet dietary recommendations and is associated with reduced risk of several chronic diseases. Long-term randomized controlled trials are needed to demonstrate the direct effects of pulses on these diseases.

Pulse consumption in Canadian adults influences nutrient intakes.

Pulses (dry beans, peas, lentils) are nutrient-dense foods that are recommended as good choices in either the vegetable or meat and alternative food groups in Canadas Food Guide. To examine the prevalence and the effect of pulse consumption on nutrient intake in Canadian adults ( ≥ 19 years), we analysed cross-sectional data (n 20,156) from the 2004 Canadian Community Health Survey, Cycle 2·2. Participants were divided into non-consumers and quartiles of pulse intake. Sample weights were applied and logistic regression analysis was used to explore the association of nutrient intakes and pulse consumption, with cultural background, sex, age and economic status included as covariates. On any given day, 13 % of Canadians consume pulses, with the highest consumption in the Asian population. The pulse intake of consumers in the highest quartile was 294 (se 40) g/d and, compared with non-consumers, these individuals had higher intakes of carbohydrate, fibre and protein. As well, the micronutrient intake of pulse consumers was enhanced, resulting in fewer individuals who were below the estimated average requirement for thiamin, vitamin B6, folate, Fe, Mg, P and Zn, compared with non-consumers. Although pulses are generally low in Na, its intake also was higher in pulse consumers. Among the higher quartiles of pulse consumers, fruit and vegetable intake was one serving higher. These data indicate that pulse consumption supports dietary advice that pulses be included in healthful diets. Further studies elucidating the sources of increased Na in pulse consumers will be necessary so that dietary advice to increase consumption of pulses will maximise their nutritional benefits.

Comorbidity increases the risk of hospitalizations in multiple sclerosis

Objective: We aimed to evaluate the association between comorbidity and rates of hospitalization in the multiple sclerosis (MS) population as compared to a matched cohort from the general population. Methods: Using population-based administrative data from the Canadian province of Manitoba, we identified 4,875 persons with MS and a matched general population cohort of 24,533 persons. We identified all acute care hospitalizations in the period 2007–2011. Using general linear models, we evaluated the association between comorbidity status and hospitalization rates (all-cause, non-MS-related, MS-related) in the 2 populations, adjusting for age, sex, and socioeconomic status. Results: Comorbidity was common in both cohorts. Over the 5-year study period, the MS population had a 1.5-fold higher hospitalization rate (adjusted rate ratio [aRR] 1.56; 95% confidence interval [CI] 1.44–1.68) than the matched population. Any comorbidity was associated with a 2-fold increased risk of non-MS-related hospitalization rates (aRR 2.21; 95% CI 1.73–2.82) in the MS population, but a nearly 4-fold increase in hospitalization rates in the matched population (aRR 3.85; 95% CI 3.40–4.35). Comorbidity was not associated with rates of hospitalization for MS-related reasons, regardless of how comorbidity status was defined. Conclusions: In the MS population, comorbidity is associated with an increased risk of all-cause hospitalizations, suggesting that the prevention and management of comorbidity may reduce hospitalizations.

Dramatically changing rates and reasons for hospitalization in multiple sclerosis.

Objective: We aimed to describe hospitalizations in the multiple sclerosis (MS) population, and to evaluate temporal trends in hospitalizations in the MS population compared to the general population. Methods: Using population-based administrative data, we identified 5,797 persons with MS and a matched general population cohort of 28,769 persons. Using general linear models, we evaluated temporal trends in hospitalization rates and length of stay in the 2 populations over the period 1984–2011. Results: In 1984 the hospitalization rate was 35 per 100 person-years in the MS population and 10.5 in the matched population (relative risk [RR] 3.33; 95% confidence interval: 1.67–6.64). Over the study period hospitalizations declined 75% in the MS population but only 41% in the matched population. The proportion of hospitalizations due to MS declined substantially from 43.4% in 1984 to 7.8% in 2011. The 3 most common non–MS-related reasons for admission in the MS population were diseases of the digestive, genitourinary, and circulatory systems. Admissions for bacterial pneumonia, influenza, urinary tract infections, and pressure ulcers occurred more often in the MS population than in the general population, while admissions for circulatory system disease and neoplasms occurred less often. Older age, male sex, and lower socioeconomic status were associated with increased hospitalization rates for non–MS-related reasons. Conclusions: Although hospitalization rates have declined dramatically in the MS population over the last quarter century, they remain higher than in the general population. Admissions for MS-related reasons now constitute only a small proportion of the reasons for hospitalization.

High rates of physician services utilization at least five years before multiple sclerosis diagnosis

Background: Multiple sclerosis (MS) management has changed over time, but changes in health care utilization by MS patients remain understudied. We estimated physician services utilization in the five-year periods before and after MS diagnosis, and over the period 1984–2008. Methods: Using administrative data we identified 4092 persons with MS and a matched general population (GPOP) cohort of 21,446 persons. Using general linear models we compared physician visits between the MS and GPOPs for the period 1984–2008, the year of MS diagnosis, and for the five-year periods pre- and post-diagnosis. Results: From 1984 to 2008, 98% of the MS population averaged ≥1 physician visits/year versus 87% of the GPOP. In 2008, the MS population had 12.9 physician visits/person-year while the GPOP had 8.4 (rate ratio (RR) 1.53; 95% confidence interval (CI): 1.52–1.55). Five years pre-MS diagnosis, the MS population had more physician visits than the GPOP (RR 1.15; 95% CI; 1.10–1.21). The number of visits peaked the year of MS diagnosis (19.0), decreasing thereafter, but remaining elevated versus the pre-diagnosis period. Conclusion: The MS population uses more physician services than the GPOP, starting at least five years pre-MS diagnosis. A better understanding of the reasons for these higher utilization rates may ultimately improve outcomes in MS.

Intake patterns and dietary associations of soya protein consumption in adults and children in the Canadian Community Health Survey, Cycle 2.2.

Soya foods are one of the recommended alternatives to meat in many dietary guidelines. While this is expected to increase the intake of some nutrients, potential concerns regarding others have been raised. The purpose of the present study was to examine the prevalence and the association of soya food consumption with nutrient intakes and dietary patterns of Canadians (age ≥ 2 years). Cross-sectional data from the 2004 Canadian Community Health Survey (Cycle 2.2; n 33,218) were used to classify soya consumers and non-consumers. Soya consumers were further divided into two groups based on their soya protein intake. Sample weights were applied and logistic regression analysis was used to explore the association between nutrient intakes and soya consumption, with cultural background, sex, age and economic status being included as covariates. On any given day, 3.3% (n 1085) of Canadians consume soya foods, with females, Asian Canadians and adults with post-secondary education being more likely to be soya consumers. As a whole, adolescent and adult respondents who had consumed at least one soya food during their 24 h dietary recall had higher energy intakes, as well as increased intakes of nutrients such as protein, fibre, vitamin C, vitamin B6, naturally occurring folate, thiamin, Ca, P, Mg, PUFA, Fe and K and lowered intakes of saturated fat. These data indicate that soya food consumption is associated with improved diet quality of Canadians. However, future research is necessary to investigate the association between increased energy intake and soya consumption.

Application of three focused cluster detection methods to study geographic variation in the incidence of multiple sclerosis in Manitoba, Canada

Background: Macroscopic geographic variation in the incidence and prevalence of MS is well-recognized. Microscopic geographic variation in the distribution of MS is also recognized, but less well-studied. Most studies have focused on prevalent cases of MS, although studies of variation in disease incidence are more relevant for developing etiologic hypotheses. We aimed to study geographic variation in the incidence of MS using three different methods. Methods: We used population-based administrative (health claims) data to identify 2,290 incident cases of MS in the province of Manitoba, Canada from 1990 to 2006. We applied three focused cluster-detection procedures, including the circular spatial scan statistic (CSS), flexible spatial scan statistic (FSS), and Bayesian disease mapping (BYM), to the dataset. Results: The CSS and FSS methods identified 30 and 26 regions as potential clusters, respectively, although the regions identified differed slightly due to the non-circular shape of some regions in Manitoba. The BYM approach identified 37 regions as potential clusters, again with some differences as compared to the other two methods. Twelve regions were identified as potential clusters by all three methods. All methods identified the western part of the city of Winnipeg as a significant cluster. Using the BYM approach, the incidence of MS was highest among areas of higher socioeconomic status. Conclusions: Two methods CSS and FSS only capture geographical variations and are not able to control for confounders at the same time which may lead to mis-identification of clusters. However, the BYM method can simultaneously identify geographical variations and control for possible confounders.