Association of urinary sodium and potassium excretion with blood pressure

BACKGROUND

Higher levels of sodium intake are reported to be associated with higher blood pressure. Whether this relationship varies according to levels of sodium or potassium intake and in different populations is unknown.

METHODS

We studied 102,216 adults from 18 countries. Estimates of 24-hour sodium and potassium excretion were made from a single fasting morning urine specimen and were used as surrogates for intake. We assessed the relationship between electrolyte excretion and blood pressure, as measured with an automated device.

RESULTS

Regression analyses showed increments of 2.11 mm Hg in systolic blood pressure and 0.78 mm Hg in diastolic blood pressure for each 1-g increment in estimated sodium excretion. The slope of this association was steeper with higher sodium intake (an increment of 2.58 mm Hg in systolic blood pressure per gram for sodium excretion >5 g per day, 1.74 mm Hg per gram for 3 to 5 g per day, and 0.74 mm Hg per gram for <3 g per day; P<0.001 for interaction). The slope of association was steeper for persons with hypertension (2.49 mm Hg per gram) than for those without hypertension (1.30 mm Hg per gram, P<0.001 for interaction) and was steeper with increased age (2.97 mm Hg per gram at >55 years of age, 2.43 mm Hg per gram at 45 to 55 years of age, and 1.96 mm Hg per gram at <45 years of age; P<0.001 for interaction). Potassium excretion was inversely associated with systolic blood pressure, with a steeper slope of association for persons with hypertension than for those without it (P<0.001) and a steeper slope with increased age (P<0.001).

CONCLUSIONS

In this study, the association of estimated intake of sodium and potassium, as determined from measurements of excretion of these cations, with blood pressure was nonlinear and was most pronounced in persons consuming high-sodium diets, persons with hypertension, and older persons. (Funded by the Heart and Stroke Foundation of Ontario and others.).

Erectile dysfunction and fruit/vegetable consumption among diabetic Canadian men

OBJECTIVE

To evaluate the association between fruit/vegetable consumption and erectile dysfunction (ED) among Canadian men with diabetes.

METHODS

Data from the 2011 Survey on Living with Chronic Diseases in Canada - Diabetes Component were analyzed using Statistical Analysis System Enterprise Guide (SAS EG). Respondents were asked a series questions related to their sociodemographics, lifestyle, and chronic health conditions. The association between fruit/vegetable consumption and ED was examined using logistic regression after controlling for potential confounding factors. Bootstrap procedure was used to estimate sample distribution and calculate confidence intervals.

RESULTS

Overall, 26.2% of respondents reported having ED. The prevalence increased with age and duration of diabetes. Compared with respondents without ED, those with ED were more likely to be obese, smokers, physically inactive, and either divorced, widowed, or separated. Diabetes complications such as nerve damage, circulation problems, and kidney failure or kidney disease were also significantly associated with ED. After controlling for potential confounding factors, a 10% risk reduction of ED was found with each additional daily serving of fruit/vegetable consumed.

CONCLUSION

ED is common among Canadian men with diabetes. ED was highly associated with age, duration of diabetes, obesity, smoking, and the presence of other diabetes-related complications. Fruit and vegetable consumption might have a protective effect against ED.

Association between mental health and fall injury in Canadian immigrants and non-immigrants

The study was to determine the association between mental health and the incidence of injury among Canadian immigrants and non-immigrants. We used data from 15,405 individuals aged 12 years or more, who were living in British Columbia, Canada, and participated in the 2007-2008 Canadian Community Health Survey (CCHS). We calculated a 12-month cumulative incidence of fall injury based on self-reporting. Logistic regression model was used to examine the association of the 12-month cumulative incidence of fall injury with immigration status and mental health before and after adjustment for covariates. The results show that self-reported mood and anxiety disorders were significantly associated with an increased incidence of fall injury. The adjusted odds ratios were 1.81 (95% CI: 1.37, 2.38) for mood disorder and 1.55 (95% CI: 1.12, 2.13) for anxiety disorder. Immigrant status was a significant effect modifier for the association between mental health and fall injury, with stronger associations in immigrants than in non-immigrants especially in elderly people. People with poor self perceived health were more likely to have a fall injury. Both mental health and general health were related to fall injury. There was a stronger association between mental health and fall injury in immigrants compared with non-immigrants in the elderly. More attention should be paid to mental health in immigrants associated with fall injury.

Long-term follow-up of kidney transplant recipients: comparison of hospitalization rates to the general population

Background

Kidney transplant recipients are recognized as a vulnerable population that is at increased risk of adverse health outcomes. However, there have been few studies that have compared hospital-related morbidity of these patients to the general population, and how this differs with respect to time since transplantation. Such analyses are useful in estimating the health burden in this patient population.

Methods

We assembled a population-based Canadian cohort (excluding Quebec) of 6,116 kidney transplant recipients who underwent transplantation between 1 April 2001 and 31 December 2008. Record linkage was used to identify hospital discharge records of these patients from 1 April 2001 through 31 March 2009. Hospital discharges were tabulated across the main disease chapters of the ICD10, and person-years of follow-up were calculated across age and sex strata. Comparisons of hospital-related morbidity to the general population were made by using a standardized hospitalization ratio (SHR). For those who underwent transplantation in 2004, stratified analyses were performed to explore differences in hospital discharge rates both before and after transplantation.

Results

After excluding hospitalizations due to complications from transplantation, when compared to the general population, transplant recipients were approximately 6.4 (95% CI: 6.3, 6.5) times more likely to be hospitalized during follow-up. The SHRs were highest during the time periods proximate to transplantation, and then decreased to approximately a five-fold increase from 3 years post transplantation onwards. The largest disease-specific excesses were observed with infectious diseases and diseases of the endocrine system. Among those who underwent transplantation in 2004, the SHR decreased from 11.2 to 5.0 in the periods before and after surgery, respectively.

Conclusions

Our results indicate that, even more than 5-years post transplantation, there remains a more than six-fold difference in hospitalization rates relative to the general population. Additional work is needed to confirm these findings, and to develop strategies to reduce long-term morbidity in this patient population.

The prevalence of human papillomavirus and its impact on cervical dysplasia in Northern Canada

Introduction

Certain types of the Human Papillomavirus (HPV) are sexually transmitted and highly associated with development of cervical dysplasia and cervical cancer but the distribution of HPV infection in the North, particularly amongst First Nations, Metis, and Inuit peoples, is little known. The purposes of the study are to identify the prevalence of type-specific HPV infections and the association of different HPV types with cervical dysplasia among women in Northern Canada.

Methods

This was a cross-sectional study with attendants of the routine or scheduled Pap testing program in the Northwest Territories (NWT), Nunavut, Labrador and Yukon, Canada. Approximately half of each sample was used for Pap test and the remaining was used for HPV genotyping using a Luminex-based method. Pap test results, HPV types, and demographic information were linked for analyses.

Results

Results from 14,598 specimens showed that HPV infection was approximately 50% higher among the Aboriginal than the non-Aboriginal population (27.6% vs. 18.5%). Although the most common HPV type detected was HPV 16 across region, the prevalence of other high risk HPV types was different. The age-specific HPV prevalence among Aboriginal showed a ‘U’ shape which contrasted to non-Aboriginal. The association of HPV infection with cervical dysplasia was similar in both Aboriginal and non-Aboriginal populations.

Conclusions

The HPV prevalence was higher in Northern Canada than in other Areas in Canada. The prevalence showed a higher rate of other high risk HPV infections but no difference of HPV 16/18 infections among Aboriginal in comparison with non-Aboriginal women. This study provides baseline information on HPV prevalence that may assist in surveillance and evaluation systems to track and assess HPV vaccine programs.

Prevalence estimates of chronic kidney disease in Canada: results of a nationally representative survey

BACKGROUND

Chronic kidney disease is an important risk factor for death and cardiovascular-related morbidity, but estimates to date of its prevalence in Canada have generally been extrapolated from the prevalence of end-stage renal disease. We used direct measures of kidney function collected from a nationally representative survey population to estimate the prevalence of chronic kidney disease among Canadian adults.

METHODS

We examined data for 3689 adult participants of cycle 1 of the Canadian Health Measures Survey (2007-2009) for the presence of chronic kidney disease. We also calculated the age-standardized prevalence of cardiovascular risk factors by chronic kidney disease group. We cross-tabulated the estimated glomerular filtration rate (eGFR) with albuminuria status.

RESULTS

The prevalence of chronic kidney disease during the period 2007-2009 was 12.5%, representing about 3 million Canadian adults. The estimated prevalence of stage 3-5 disease was 3.1% (0.73 million adults) and albuminuria 10.3% (2.4 million adults). The prevalence of diabetes, hypertension and hypertriglyceridemia were all significantly higher among adults with chronic kidney disease than among those without it. The prevalence of albuminuria was high, even among those whose eGFR was 90 mL/min per 1.73 m(2) or greater (10.1%) and those without diabetes or hypertension (9.3%). Awareness of kidney dysfunction among adults with stage 3-5 chronic kidney disease was low (12.0%).

INTERPRETATION

The prevalence of kidney dysfunction was substantial in the survey population, including individuals without hypertension or diabetes, conditions most likely to prompt screening for kidney dysfunction. These findings highlight the potential for missed opportunities for early intervention and secondary prevention of chronic kidney disease.

Breast cancer detection and survival among women with cosmetic breast implants: systematic review and meta-analysis of observational studies

OBJECTIVES

To evaluate whether the stage distribution among women diagnosed as having breast cancer differs between those who have received breast implants for cosmetic purposes and those with no implants and to evaluate whether cosmetic breast augmentation before the detection of breast cancer is a predictor of post-diagnosis survival.

DESIGN

Systematic review of observational studies with two meta-analyses.

DATA SOURCES

Systematic search of the literature published before September 2012 conducted in Medline, Embase, Global health, CINAHL, IPAB, and PsycINFO.

STUDY SELECTION

Eligible publications were those that included women diagnosed as having breast cancer and who had had augmentation mammaplasty for cosmetic purposes.

RESULTS

The overall odds ratio of the first meta-analysis based on 12 studies was 1.26 (95% confidence interval 0.99 to 1.60; P=0.058; I(2)=35.6%) for a non-localized stage of breast cancer at diagnosis comparing women with implants who had breast cancer and women without implants who had breast cancer. The second meta-analysis, based on five studies, evaluated the relation between cosmetic breast implantation and survival. This meta-analysis showed reduced survival after breast cancer among women who had implants compared with those who did not (overall hazard ratio for breast cancer specific mortality 1.38, 95% confidence interval 1.08 to 1.75).

CONCLUSIONS

The research published to date suggests that cosmetic breast augmentation adversely affects the survival of women who are subsequently diagnosed as having breast cancer. These findings should be interpreted with caution, as some studies included in the meta-analysis on survival did not adjust for potential confounders. Further investigations are warranted regarding diagnosis and prognosis of breast cancer among women with breast implants.

A cohort study for the impact of activity-limiting injuries based on the Canadian National Population Health Survey 1994-2006

OBJECTIVE

To examine the prevalence and factors affecting activity-limiting injuries (ALI) in individuals and in the Canadian population; to estimate the short and long term impact on health status and well-being because of ALI in Canada from 1994 to 2006 using the Canadian National Population Health Survey (NPHS).

DESIGN

The NPHS is a randomised longitudinal cohort study with biennial interviews, with information on age, sex, education, marital status, income, residence, height and weight to self-perceived health status, healthcare utilisation and medication use in addition to ALI.

SETTING

The study population was a random sample of male and female participants 20 years and older from 10 provinces and three territories in Canada.

PRIMARY AND SECONDARY OUTCOME MEASURES

Logistic regression models were used to assess the potential impact of ALI on individuals and on the Canadian population. The interviews 2 years before and 2 years after the ALI were compared to examine long-term effects, and the McNemar test option in SAS was used for the matched analysis.

RESULTS

The immediate impacts of ALI were pain, disability and disruption of regular life. Long-term effects in patients were chronic pain and increased medical doctor visits. Population impact included a considerable increase in healthcare access and cost. The odds ratios (OR) for the 20-39 age group compared with those 60+ was 2.2; 95% CI 1.8 to 2.7, while the OR associated with male participants was 1.4; 95% CI 1.1 to 1.6. Individuals consuming nine or more alcoholic drinks per week were also significantly more likely to report an ALI (OR, 1.5; 95% CI 1.3 to 1.8).

CONCLUSIONS

The findings from this study illustrated the immediate and long-term impact of individuals and population level injuries in Canada. Injury control policies should aim to prevent the number of injuries, fatalities as well as the consequences among survivors.

Type-specific prevalence of human papillomavirus in women screened for cervical cancer in Labrador, Canada

Background

A higher incidence of cervical cancer and human papillomavirus (HPV) infection has been reported in northern Canada and in First Nation, Métis and Inuit women, with some evidence to suggest that the HPV type distribution in these populations may be different from the rest of Canada.

Objective

The objective of this study was to measure the HPV type prevalence in Labrador women to determine if significant differences in HPV types could reduce the effectiveness of HPV vaccination.

Design

The prevalence of HPV types was determined in 1,370 women presenting for routine pap screening in Labrador between February and November 2010. Cervical cytology and HPV genotyping were performed on the same liquid-based cytology specimens.

Results

The overall prevalence of HPV was 21.4%; cytological abnormalities were found in 8.8% of the participants. HPV 16 and 18 were the most common high-risk HPV types. These two types were found in 52.4% of high-grade lesions. The prevalence in HPV infections was comparable across the Labrador regions.

Conclusions

The present results support the potential effectiveness of the HPV immunization program in Labrador.

Perinatal and early childhood factors for overweight and obesity in young Canadian children

BACKGROUND

This study assessed potential early-life factors and their interrelationships with obesity among young Canadian children.

METHODS

Data from a nationally representative sample of children aged 6 to 11 years in the Canadian Health Measures Survey were analyzed. The associations of perinatal and early childhood behaviours and socio-economic factors with overweight or obesity were evaluated using multivariate logistic regression models. Adjusted population attributable risk fractions (PARFs) were calculated using multivariate logistic regression models.

RESULTS

Of 968 term-born children, 21% were overweight and another 13% were obese. Maternal smoking during pregnancy (adjusted odds ratio, 2.26; 95% confidence interval, 1.23-4.15) was positively associated with obesity. This association was mediated by birth weight (suppression effect); once controlled, the strength of the association between smoking and child obesity increased by 12%. Birth weight per 100 g (1.05; 1.005-1.09) was significantly associated with obesity. Exclusive breastfeeding for 6 months (0.44; 0.31-0.61), adequate sleep hours (0.39; 0.16-0.94) and being physically active (0.50; 0.26-0.93) were found to be protective. Breastfeeding, whether exclusive or not, significantly reduced obesity risk among children whose mothers never smoked in pregnancy. PARFs indicated that 24.4%, 11.5%, 11.3% and 6.0% prevalent cases of child obesity might be prevented by exclusive breastfeeding, smoking cessation during pregnancy, adequate sleep during childhood, and avoiding high birth weight, respectively.

CONCLUSIONS

This study identified multiple perinatal and childhood factors associated with obesity in young Canadian children. Effective prevention strategies targeting four modifiable maternal and child risk factors may reduce childhood obesity by up to 54% in Canada.

Long-term association between leisure-time physical activity and changes in happiness: analysis of the Prospective National Population Health Survey

Happiness is among the most fundamental of all human goals. Although the short-term association between physical activity and happiness is well known, the long-term associations are not. Data from the National Population Health Survey cycles conducted between 1994/1995 and 2008/2009 (cycles 1 through 8) were analyzed. Happy respondents were classified as physically active or inactive at baseline and then were followed up in subsequent cycles to examine their likelihood of becoming unhappy. Individuals who changed their activity level also were examined. After controlling for potential confounding factors, the authors found that leisure-time physical activity (LTPA) was associated with reduced odds of unhappiness after 2 years and 4 years. People who were inactive in 2 consecutive cycles were more than twice as likely to be unhappy as those who remained active in both cycles after 2 years. Compared with those who became active, inactive participants who remained inactive were also more likely to become unhappy. A change in LTPA from active to inactive was associated with increased odds of becoming unhappy 2 years later. This study suggests that LTPA has a long-term association with happiness. Changes in LTPA are associated with subsequent mood status.

Glycemic index, glycemic load and cancer risk

BACKGROUND

Dietary glycemic index (GI) and glycemic load (GL) have been related to the risk of selected cancers, but the issue remains open.

PATIENTS AND METHODS

Mailed questionnaires were completed between 1994 and 1997 in eight Canadian provinces for incident, histologically confirmed cases of the stomach (n=1182), colon (n=1727), rectum (n=1447), liver (n=309), pancreas (n=628), lung (n=3341), breast (n=2362), ovary (n=442), prostate (n=1799), testis (n=686), kidney (n=1345), bladder (n=1029), brain (n=1009), non-Hodgkin's lymphomas (NHL, n=1666), leukemias (n=1069), multiple myelomas (n=343), and 5039 population controls. Dietary information on eating habits 2 years before participants' enrollment in the study was obtained using a validated food frequency questionnaire (FFQ). Odds ratios (ORs) and 95% confidence intervals (CI) were derived by unconditional logistic regression including recognized confounding factors.

RESULTS

Dietary GI was positively associated with the risk of prostate cancer (OR, 1.26 for the highest versus the lowest quartile). A higher dietary GL significantly increased the risk of colorectal (OR, 1.28), rectal (OR, 1.44) and pancreatic (OR, 1.41) cancers. No other significant associations were found.

CONCLUSIONS

Our findings suggest that a diet high in GI and GL is associated with increased risk of selected cancers.

Factors associated with human papillomavirus infection among women in the Northwest Territories

BACKGROUND

In some regions, Aboriginal women have higher rates of cervical cancer compared to other Canadian women. However, little data are available regarding the co-factors of HPV infection in the Aboriginal population of Canada. We examined factors associated with high-risk human papillomavirus (HR-HPV) infection in a population of women (both Aboriginal and non-Aboriginal) in the Northwest Territories (NWT).

METHODS

We used a cross-sectional design using a convenience sample of all women aged 14 years or older presenting for Papanicolaou (Pap) testing across all regions of the NWT from March 2009 to March 2010. Women answered a questionnaire on demographic characteristics, sexual behaviour, and gynaecological and obstetrical events. We used multiple regression analysis to explore factors associated with HR-HPV infection according to age and cultural background. HPV typing was done using the Luminex assay.

RESULTS

Of the total 1,279 participants, 178 had missing HPV results. We obtained data on 1,101 women and overall HR-HPV prevalence was 14.2%. Younger age, single marital status, Aboriginal background, current smoking, lifetime deliveries, use of hormonal contraceptives, and the numbers of sexual partners in the last year were associated with prevalent HR-HPV.

DISCUSSION

Our findings tend to indicate that Aboriginal women have different predictors of HR-HPV than non-Aboriginal women that may affect HPV progression to cervical cancer. These findings can help to better target public health practices for the women at higher risk of HPV infection and cervical cancer.

Increasing blood pressure and its associated factors in Canadian children and adolescents from the Canadian Health Measures Survey

BACKGROUND

Canada is facing a childhood obesity epidemic. Elevated blood pressure (BP) is a major complication of obesity. Reports on the impact of excess adiposity on BP in children and adolescents have varied significantly across studies. We evaluated the independent effects of obesity, physical activity, family history of hypertension, and socioeconomic status on BP in a nationally representative sample of children and adolescents.

METHODS

We analysed cross-sectional data for 1850 children aged 6 to 17 years who participated in the Canadian Health Measures Survey, Cycle 1, 2007-2009. Systolic BP (SBP) and diastolic BP (DBP) were age-, sex-, and height-adjusted to z-scores (SBPZ and DBPZ). Body mass index (BMI) z-scores were calculated based on World Health Organization growth standards. Multivariate linear regression was used to evaluate the independent effects of relevant variables on SBPZ and DBPZ.

RESULTS

For most age/sex groups, obesity was positively associated with SBP. Being obese was associated with higher DBP in adolescent boys only. The BP effect of obesity showed earlier in young girls than boys. Obese adolescents were estimated to have an average 7.6 mmHg higher SBP than normal weight adolescents. BMI had the strongest effect on BP among obese children and adolescents. Moderately active adolescent boys had higher SBP (3.9 mmHg) and DBP (4.9 mmHg) than physically active boys. Family history of hypertension showed effects on SBP and DBP in younger girls and adolescent boys. Both family income and parent education demonstrated independent associations with BP in young children.

CONCLUSIONS

Our findings demonstrate the early impact of excess adiposity, insufficient physical activity, family history of hypertension, and socioeconomic inequalities on BP. Early interventions to reduce childhood obesity can, among other things, reduce exposure to prolonged BP elevation and the future risk of cardiovascular disease.

Canadian breast implant cohort: extended follow-up of cancer incidence

Cosmetic breast implants are not associated with increased breast cancer incidence, but variations of risk according to implant characteristics are still poorly understood. As well, the assessment of cancer risk for sites other than breast needs to be clarified. The purpose of this study was to fill these research gaps. This study presents an extended analysis of 10 more years of follow-up of a large Canadian cohort of women who received either cosmetic breast implants (n = 24,558) or other cosmetic surgery (15,893). Over 70% of the implant cohort was followed for over 20 years. Cancer incidence among implant women was compared to those of controls using multivariate Poisson models and the general female population using the standardized incidence ratios (SIRs). Women with breast implants had reduced rates of breast and endometrial cancers compared to other surgery women. Subglandular implants were associated to a reduced rate of breast cancer compared to submuscular implants [incidence rate ratio (IRR) = 0.78, 95% confidence interval (CI) = 0.63-0.96] and this reduction persisted over time. We observed a sevenfold increased rate (IRR = 7.36, 95% CI = 1.86-29.12) of breast cancer in the first 5 years after the date of surgery for polyurethane-coated subglandular implant women but this IRR decreased progressively over time (p value for trend = 0.02). We also observed no increased risk of rarer forms of cancer among augmented women. A reduction in breast cancer incidence was observed for women with subglandular implants relative to women with submuscular implants. Possible increase of breast cancer incidence shortly after breast augmentation with polyurethane implants needs to be verified.

Migration and diabetes in British Columbia and Quebec: prevalence and health service utilization

OBJECTIVES

This study describes prevalence of diabetes among immigrants and health service utilization among diabetic immigrants in British Columbia (BC) and Quebec (QC).

METHODS

Immigrants to BC and QC between 1985 and 1999 were identified. Using age-standardized rate ratios, they were compared with a matched comparison group with respect to their diabetes prevalence and, among those with diabetes, physician service utilization.

RESULTS

Immigrant women in both provinces and men in BC had higher rates of diabetes compared to the matched comparison group. Rates varied by region of birth and language ability. Diabetes prevalence rate ratios increased with length of stay in BC. Diabetic immigrants had lower rates of physician visits than diabetic comparisons. This gap decreased commensurate with immigrants' length of stay in BC. Diabetic immigrants who spoke neither official language had similar or higher rates of physician visits compared with immigrants who spoke one or both official languages.

CONCLUSIONS

Genetic predisposition, lifestyle changes, acculturation, resettlement stress and differential health care access may explain increased prevalence of diabetes among many immigrants. These results can inform diabetes prevention and management programs tailored to the needs of specific immigrant groups. The gap in health service use between diabetic immigrants and comparisons does not appear to be related to language ability. Further studies are required to identify reasons.

Plasma vitamin D levels and risk of metabolic syndrome in Canadians

Purpose: Vitamin D deficiency has been implicated in susceptibility to the development of metabolic syndrome, obesity and type 2 diabetes mellitus. The present study aimed to quantify the association between vitamin D plasma level, the number of metabolic syndrome components and insulin resistance in Canadians. Methods: Vitamin D plasma level and clinical data were determined from 1,818 subjects from the Canadian Health Measures Survey; a representative health survey of the general population of Canada conducted from 2007 to 2009. The definition of metabolic syndrome was based on the National Cholesterol Education Program, Adult Treatment Panel III criteria. Adjusted general linear models were used to estimate the association between vitamin D level and probability of having metabolic syndrome, as well as the association between plasma vitamin D and insulin resistance (homeostasis model assessment for insulin resistance, or HOMA-IR). Results: The prevalence of metabolic syndrome in the study population was 8.9%. The number of metabolic syndrome components was inversely correlated with plasma vitamin D level (ρ= -0.1, p < 0.0001). Subjects in the highest vitamin D quartile had lower odds ratio of metabolic syndrome compared with their counterparts in the lowest vitamin D quartile (0.50, 95% CI= 0.24-1.06). Increasing plasma vitamin D level (by 10 nmol/L) was inversely associated with HOMA-IR score (β= -0.08, p=0.006) in a model adjusted for physical activity, smoking status, month of interview, age, sex and ethnicity. Conclusion: Vitamin D plasma levels are associated with the occurrence of metabolic syndrome components and insulin resistance among Canadians and are linked to increased level of insulin resistance.