To ascertain whether objectively measured obstructive sleep apnea (OSA) independently increases the risk of all cause death, cardiovascular disease (CVD), coronary heart disease (CHD), stroke or ...cancer.
Community-based cohort.
400 residents of the Western Australian town of Busselton.
OSA severity was quantified via the respiratory disturbance index (RDI) as measured by a single night recording in November-December 1990 using the MESAM IV device, along with a range of other risk factors. Follow-up for deaths and hospitalizations was ascertained via record linkage to the end of 2010.
We had follow-up data in 397 people and then removed those with a previous stroke (n = 4) from the mortality/ CVD/CHD/stroke analyses and those with cancer history from the cancer analyses (n = 7). There were 77 deaths, 103 cardiovascular events (31 strokes, 59 CHD) and 125 incident cases of cancer (39 cancer fatalities) during 20 years follow-up. In fully adjusted models, moderate-severe OSA was significantly associated with all-cause mortality (HR = 4.2; 95% CI 1.9, 9.2), cancer mortality (3.4; 1.1, 10.2), incident cancer (2.5; 1.2, 5.0), and stroke (3.7; 1.2, 11.8), but not significantly with CVD (1.9; 0.75, 4.6) or CHD incidence (1.1; 0.24, 4.6). Mild sleep apnea was associated with a halving in mortality (0.5; 0.27, 0.99), but no other outcome, after control for leading risk factors.
Moderate-to-severe sleep apnea is independently associated with a large increased risk of all-cause mortality, incident stroke, and cancer incidence and mortality in this community-based sample.
The purpose of the present analysis was to use longitudinal data collected over 7 years (from 4 surveys) in the Residential Environments (RESIDE) Study (Perth, Australia, 2003-2012) to more carefully ...examine the relationship of neighborhood walkability and destination accessibility with walking for transportation that has been seen in many cross-sectional studies. We compared effect estimates from 3 types of logistic regression models: 2 that utilize all available data (a population marginal model and a subject-level mixed model) and a third subject-level conditional model that exclusively uses within-person longitudinal evidence. The results support the evidence that neighborhood walkability (especially land-use mix and street connectivity), local access to public transit stops, and variety in the types of local destinations are important determinants of walking for transportation. The similarity of subject-level effect estimates from logistic mixed models and those from conditional logistic models indicates that there is little or no bias from uncontrolled time-constant residential preference (self-selection) factors; however, confounding by uncontrolled time-varying factors, such as health status, remains a possibility. These findings provide policy makers and urban planners with further evidence that certain features of the built environment may be important in the design of neighborhoods to increase walking for transportation and meet the health needs of residents.
Understanding the relationship between urban design and physical activity is a high priority. Different representations of land use diversity may impact the association between neighbourhood design ...and specific walking behaviours. This study examined different entropy based computations of land use mix (LUM) used in the development of walkability indices (WIs) and their association with walking behaviour.
Participants in the RESIDential Environments project (RESIDE) self-reported mins/week of recreational, transport and total walking using the Neighbourhood Physical Activity Questionnaire (n = 1798). Land use categories were incrementally added to test five different LUM models to identify the strongest associations with recreational, transport and total walking. Logistic regression was used to analyse associations between WIs and walking behaviour using three cut points: any (> 0 mins), ≥ 60 mins and ≥ 150 mins walking/week.
Participants in high (vs. low) walkable neighbourhoods reported up to almost twice the amount of walking, irrespective of the LUM measure used. However, different computations of LUM were found to be relevant for different types and amounts of walking (i.e., > 0, ≥ 60 or ≥ 150 mins/week). Transport walking (≥ 60 mins/week) had the strongest and most significant association (OR = 2.24; 95% CI:1.58-3.18) with the WI when the LUM included 'residential', 'retail', 'office', 'health, welfare and community', and 'entertainment, culture and recreation'. However, any (> 0 mins/week) recreational walking was more strongly associated with the WI (OR = 1.36; 95% CI:1.04-1.78) when land use categories included 'public open space', 'sporting infrastructure' and 'primary and rural' land uses. The observed associations were generally stronger for ≥ 60 mins/week compared with > 0 mins/week of transport walking and total walking but this relationship was not seen for recreational walking.
Varying the combination of land uses in the LUM calculation of WIs affects the strength of relationships with different types (and amounts) of walking. Future research should examine the relationship between walkability and specific types and different amounts of walking. Our results provide an important first step towards developing a context-specific WI that is associated with recreational walking. Inherent problems with administrative data and the use of entropy formulas for the calculation of LUM highlight the need to explore alternative or complimentary measures of the environment.
Non-alcoholic fatty liver disease (NAFLD) uncommonly results in cirrhosis and liver-related death; however, its impact on the development of metabolic complications remains unclear. We sought to ...determine whether NAFLD with elevated aminotransaminase (ALT) levels was a risk factor for incident diabetes or the metabolic syndrome (MS) over an 11-year period.
Adult residents of Busselton, Western Australia underwent assessment in 1994-1995 as part of the Busselton Health Survey. NAFLD was diagnosed on the basis of a raised ALT (>40 IU/l) after the exclusion of alcohol, viral, metabolic, and autoimmune liver disease. NAFLD and non-NAFLD subjects were reassessed in 2005 for liver complications, diabetes, and the MS.
A total of 358 subjects, 68% male (109 NAFLD, 249 non-NAFLD), mean age (s.d.) 59.9 (11.6) years, attended follow-up 11.1 years after the initial assessment. After excluding subjects with diabetes at baseline, those with NAFLD were more likely to have developed diabetes on follow-up (20/106, 18.9% vs. 15/246, 6.1%; P<0.001). After excluding subjects with MS at baseline, those with NAFLD were more likely to have developed MS at follow-up (27/81, 33.3% vs. 51/226, 22.6%; P=0.056). However, in multivariate logistic regression models, NAFLD was no longer a significant independent predictor of the development of diabetes or MS after adjusting for baseline waist circumference, hypertension, and insulin resistance. None of the subjects developed liver complications.
Subjects with NAFLD and elevated ALT levels are at an increased risk of developing diabetes and the MS. This may be because of the presence of associated metabolic risk factors.
Previously published cohort studies in clinical populations have suggested that obstructive sleep apnea (OSA) is a risk factor for mortality associated with cardiovascular disease. However, it is ...unknown whether sleep apnea is an independent risk factor for all-cause mortality in a community-based sample free from clinical referral bias.
Residents of the Western Australian town of Busselton underwent investigation with a home sleep apnea monitoring device (MESAM IV). OSA was quantified via the respiratory disturbance index (RDI). Mortality status was determined in 397/400 participants (99.3%) after up to 14 years (mean follow-up 13.4 years) by data matching with the Australian National Death Index and the Western Australian Death Register. Univariate analyses and multivariate Cox proportional hazards modelling were used to ascertain the association between sleep apnea and mortality after adjustment for age, gender, body mass index, mean arterial pressure, total cholesterol, high-density lipoprotein cholesterol, diabetes, and medically diagnosed angina in those free from heart attack or stroke at baseline (n = 380).
Among the 380 participants, 18 had moderate-severe OSA (RDI > or = 15/hr, 6 deaths) and 77 had mild OSA(RDI 5 to < 15/hr, 5 deaths). Moderate-to-severe OSA was independently associated with greater risk of all-cause mortality (fully adjusted hazard ratio HR = 6.24, 95% CL 2.01, 19.39) than non-OSA (n = 285, 22 deaths). Mild OSA (RDI 5 to < 15/hr) was not an independent risk factor for higher mortality (HR = 0.47, 95% CL 0.17, 1.29).
Moderate-to-severe sleep apnea is independently associated with a large increased risk of all-cause mortality in this community-based sample.
Abstract
Background and objective
Chronic medical conditions accumulate within individuals with age. However, knowledge concerning the trends, patterns and determinants of multimorbidity remains ...limited. This study assessed the prevalence and patterns of multimorbidity using extensive individual phenotyping in a general population of Australian middle-aged adults.
Methods
Participants (
n
= 5029, 55% female), born between 1946 and 1964 and attending the cross-sectional phase of the Busselton Healthy Ageing Study (BHAS) between 2010 and 2015, were studied. Prevalence of 21 chronic conditions was estimated using clinical measurement, validated instrument scores and/or self-reported doctor-diagnosis. Non-random patterns of multimorbidity were explored using observed/expected (O/E) prevalence ratios and latent class analysis (LCA). Variables associated with numbers of conditions and class of multimorbidity were investigated.
Results
The individual prevalence of 21 chronic conditions ranged from 2 to 54% and multimorbidity was common with 73% of the cohort having 2 or more chronic conditions. (mean ± SD 2.75 ± 1.84, median = 2.00, range 0–13). The prevalence of multimorbidity increased with age, obesity, physical inactivity, tobacco smoking and family history of asthma, diabetes, myocardial infarct or cancer. There were 13 pairs and 27 triplets of conditions identified with a prevalence > 1.5% and O/E > 1.5. Of the triplets, arthritis (> 50%), bowel disease (> 33%) and depression-anxiety (> 33%) were observed most commonly. LCA modelling identified 4 statistically and clinically distinct classes of multimorbidity labelled as: 1) “Healthy” (70%) with average of 1.95 conditions; 2) “Respiratory and Atopy” (11%, 3.65 conditions); 3) “Non-cardiometabolic” (14%, 4.77 conditions), and 4) “Cardiometabolic” (5%, 6.32 conditions). Predictors of multimorbidity class membership differed between classes and differed from predictors of number of co-occurring conditions.
Conclusion
Multimorbidity is common among middle-aged adults from a general population. Some conditions associated with ageing such as arthritis, bowel disease and depression-anxiety co-occur in clinically distinct patterns and at higher prevalence than expected by chance. These findings may inform further studies into shared biological and environmental causes of co-occurring conditions of ageing. Recognition of distinct patterns of multimorbidity may aid in a holistic approach to care management in individuals presenting with multiple chronic conditions, while also guiding health resource allocation in ageing populations.
The physical environment plays an important role in influencing participation in physical activity, although the specific factors that are correlated with different patterns of walking remain to be ...determined. We examined correlations between physical environmental factors and self-reported walking for recreation and transport near home.
The local neighborhood environments (defined as a 400-m radius from the respondent's home) of 1678 adults were assessed for their suitability for walking. The environmental data were collected during 2000 using the Systematic Pedestrian and Cycling Environmental Scan (SPACES) instrument together with information from other sources. We used logistic regression modeling to examine the relationship between the attributes of the physical environment and the self-reported walking behavior undertaken near home.
Functional features were correlated with both walking for recreation (odds ratio (OR) 1.62; 95% confidence interval (CI): 1.20-2.19) and for transport (OR 1.30; 95% CI: 0.97-1.73). A well-maintained walking surface was the main functional factor associated with walking for recreation (OR 2.04; 95% CI: 1.43-2.91) and for transport (OR 2.13; 95% CI: 1.53-2.96). Destination factors, such as shops and public transport, were significantly correlated with walking for transport (OR 1.80; 95% CI: 1.33-2.44), but not recreation.
The findings suggest that neighborhoods with pedestrian facilities that are attractive and comfortable and where there are local destinations (such as shops and public transport) are associated with walking near home.
Purpose
Non-adherence to heart failure (HF) medications is associated with poor outcomes. We used restricted cubic splines (RCS) to assess the continuous relationship between adherence to ...renin-angiotensin system inhibitors (RASI) and β-blockers and long-term outcomes in senior HF patients.
Methods
We identified a population-based cohort of 4234 patients, aged 65–84 years, 56% male, who were hospitalised for HF in Western Australia between 2003 and 2008 and survived to 1-year post-discharge (landmark date). Adherence was calculated using the proportion of days covered (PDC) in the first year post-discharge. RCS Cox proportional-hazards models were applied to determine the relationship between adherence and all-cause death and death/HF readmission at 1 and 3 years after the landmark date.
Results
RCS analysis showed a curvilinear adherence-outcome relationship for both RASI and β-blockers which was linear above PDC 60%. For each 10% increase in RASI and β-blocker adherence above this level, the adjusted hazard ratio for 1-year all-cause death fell by an average of 6.6% and 4.8% respectively (trend
p
< 0.05) and risk of all-cause death/HF readmission fell by 5.4% and 5.8% respectively (trend
p
< 0.005). Linear reductions in adjusted risk for these outcomes at PDC ≥ 60% were also seen at 3 years after landmark date (all trend
p
< 0.05).
Conclusion
RCS analysis showed that for RASI and β-blockers, there was no upper adherence level (threshold) above 60% where risk reduction did not continue to occur. Therefore, interventions should maximise adherence to these disease-modifying HF pharmacotherapies to improve long-term outcomes after hospitalised HF.
Population health behaviour and risk factor surveys most often rely on self-report but there is a lack of studies assessing the validity of self-report using Australian data. This study investigates ...the sensitivity, specificity and agreement of self-reported hypertension and hypercholesterolaemia with objective measures at standard and more stringent diagnostic thresholds; and factors associated with sensitivity and specificity of self-report at different thresholds.
This study was a secondary analysis of a representative community-based cross-sectional sample of 5,092 adults, aged 45-69 years, residing in Busselton, Western Australia, surveyed in 2010-2015. Participants completed a self-administered questionnaire. Blood pressure and serum cholesterol levels were measured.
At currently accepted diagnostic thresholds, sensitivities of self-reported hypertension and hypercholesterolaemia were 58.5% and 39.6%, respectively and specificities were >90% for both. Agreement using Cohen's kappa coefficient was 0.562 and 0.223, respectively. At two higher diagnostic thresholds, sensitivities of self-reported hypertension and hypercholesterolaemia improved by an absolute 14-23% and 15-25%, respectively and specificities remained >85%. Agreement was substantial for hypertension (kappa = 0.682-0.717) and moderate for hypercholesterolaemia (kappa = 0.458-0.533). Variables that were independently associated with higher sensitivity and lower specificity of self-report were largely consistent across thresholds and included increasing age, body mass index, worse self-rated health, diabetes and family history of hypertension.
Self-reported hypertension and hypercholesterolaemia often misclassify individuals' objective status and underestimate objective prevalences, at standard diagnostic thresholds, which has implications for surveillance studies that rely on self-reported data. Self-reports of hypertension, however, may be reasonable indicators of those with blood pressures ≥160/100 mmHg or those taking anti-hypertensive medications. Self-reported hypercholesterolaemia data should be used with caution at all thresholds.
Thyroid hormones modulate proliferative, metabolic and angiogenic pathways. However few studies have examined associations of thyroid hormones with cancer risk.
To explore associations of thyrotropin ...(TSH), free thyroxine (FT4) and anti-thyroperoxidase antibodies (TPOAb) with the incidence of all (non-skin) cancers and specific common cancers.
A prospective cohort study of a community-dwelling population aged 25-84 years in Western Australia.
Archived sera from 3649 participants in the 1994/1995 Busselton Health Survey were assayed for TSH, FT4 and TPOAb. Cancer outcomes until 30 June 2014 were ascertained using data linkage. Longitudinal analyses were performed using Cox proportional hazards regression.
During 20-year follow-up, 600 participants were diagnosed with non-skin cancer, including 126, 100, 103 and 41 prostate, breast, colorectal and lung cancers respectively. Higher TSH was associated with a lower risk of prostate cancer after adjusting for potential confounders, with a 30% lower risk for every 1 IU/L increase in TSH (adjusted hazard ratio (HR): 0.70, 95% confidence interval (CI): 0.55-0.90,
= 0.005). Similarly, higher FT4 was associated with an increased risk of prostate cancer (adjusted HR: 1.11 per 1 pmol/L increase, 95% CI: 1.03-1.19,
= 0.009). There were no associations of TSH, FT4 or TPOAb with all non-skin cancer events combined, or with breast, colorectal or lung cancer.
In a community-dwelling population, lower TSH and higher FT4 were associated with an increased risk of prostate cancer. Further studies are required to assess if thyroid function is a biomarker or risk factor for prostate cancer.
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