Predicting multifaceted risks using machine learning in atrial fibrillation: insights from GLORIA-AF study

Aims

Patients with atrial fibrillation (AF) have a higher risk of ischaemic stroke and death. While anticoagulants are effective at reducing these risks, they increase the risk of bleeding. Current clinical risk scores only perform modestly in predicting adverse outcomes, especially for the outcome of death. We aimed to test the multi-label gradient boosting decision tree (ML-GBDT) model in predicting risks for adverse outcomes in a prospective global AF registry.

Methods and results

We studied patients from phase II/III of the Global Registry on Long-Term Oral Anti-Thrombotic Treatment in Patients with Atrial Fibrillation registry between 2011 and 2020. The outcomes were all-cause death, ischaemic stroke, and major bleeding within 1 year following the AF. We trained the ML-GBDT model and compared its discrimination with the clinical scores in predicting patient outcomes. A total of 25 656 patients were included [mean age 70.3 years (SD 10.3); 44.8% female]. Within 1 year after AF, ischaemic stroke occurred in 215 (0.8%), major bleeding in 405 (1.6%), and death in 897 (3.5%) patients. Our model achieved an optimized area under the curve in predicting death (0.785, 95% CI: 0.757-0.813) compared with the Charlson Comorbidity Index (0.747, P = 0.007), ischaemic stroke (0.691, 0.626-0.756) compared with CHA2DS2-VASc (0.613, P = 0.028), and major bleeding (0.698, 0.651-0.745) as opposed to HAS-BLED (0.607, P = 0.002), with improvement in net reclassification index (10.0, 12.5, and 23.6%, respectively).

Conclusion

The ML-GBDT model outperformed clinical risk scores in predicting the risks in patients with AF. This approach could be used as a single multifaceted holistic tool to optimize patient risk assessment and mitigate adverse outcomes when managing AF.

Performance of multilabel machine learning models and risk stratification schemas for predicting stroke and bleeding risk in patients with non-valvular atrial fibrillation

BACKGROUND

Appropriate anticoagulant therapy for patients with atrial fibrillation (AF) requires assessment of stroke and bleeding risks. However, risk stratification schemas such as CHA2DS2-VASc and HAS-BLED have modest predictive capacity for patients with AF. Multilabel machine learning (ML) techniques may improve predictive performance and support decision-making for anticoagulant therapy. We compared the performance of multilabel ML models with the currently used risk scores for predicting outcomes in AF patients.

METHODS

This was a retrospective cohort study of 9670 patients, mean age 76.9 years, 46% women, who were hospitalized with non-valvular AF, and had 1-year follow-up. The outcomes were ischemic stroke (167), major bleeding (430) admissions, all-cause death (1912) and event-free survival (7387). Discrimination and calibration of ML models were compared with clinical risk scores by area under the curve (AUC). Risk stratification was assessed using net reclassification index (NRI).

RESULTS

Multilabel gradient boosting classifier chain provided the best AUCs for stroke (0.685 95% CI 0.676, 0.694), major bleeding (0.709 95% CI 0.703, 0.716) and death (0.765 95% CI 0.763, 0.768) compared to multi-layer neural networks and classifier chain using support vector machine. It provided modest performance improvement for stroke compared to AUC of CHA2DS2-VASc (0.652, NRI = 3.2%, p-value = 0.1), but significantly improved major bleeding prediction compared to AUC of HAS-BLED (0.522, NRI = 22.8%, p-value < 0.05). It also achieved greater discriminant power for death compared with AUC of CHA2DS2-VASc (0.606, p-value < 0.05). ML models identified additional risk features such as hemoglobin level, renal function.

CONCLUSIONS

Multilabel ML models can outperform clinical risk stratification scores for predicting the risk of major bleeding and death in non-valvular AF patients.

Alcohol Consumption and Cardiovascular Outcomes in Patients With Nonalcoholic Fatty Liver Disease: A Population-Based Cohort Study

Low-level alcohol consumption is associated with reduced cardiovascular disease (CVD) in the general population. It is unclear whether this association is seen in patients with nonalcoholic fatty liver disease (NAFLD) who have an increased risk of CVD. We examined the association between alcohol consumption and CVD-related outcomes in subjects with NAFLD from a general population cohort. Subjects participating in the 1994-1995 Busselton Health survey underwent clinical and biochemical assessment. NAFLD was identified using the Fatty Liver Index of >60, and alcohol consumption quantified using a validated questionnaire. CVD hospitalizations and death during the ensuing 20 years were ascertained using the Western Australian data linkage system. A total of 659 of 4,843 patients were diagnosed with NAFLD. The average standard drinks per week was 8.0 for men and 4.0 for women. Men consuming 8-21 drinks per week had a 38% (hazard ratio [HR] 0.62, 95% confidence interval [CI] 0.43-0.90) lower risk of CVD hospitalization as compared with men consuming 1-7 drinks per week. With both men and women combined, consumption of 8-21 drinks per week was associated with a 32% (HR 0.68, 95% CI 0.49-0.93) reduction in CVD hospitalization in minimally adjusted and 29% (HR 0.71, 95% CI 0.51-0.99) in fully adjusted models. No protective association was observed with binge drinking. There was no association between alcohol consumption and CVD death. Conclusion: Low to moderate alcohol consumption is associated with fewer CVD hospitalizations but not CVD death in subjects with NAFLD.

Impact of Pre-Hospital Activation of STEMI on False Positive Activation Rate and Door to Balloon Time

BACKGROUND

Pre-hospital identification of ST-segment elevation myocardial infarction (STEMI) by paramedical staff reduces reperfusion time. However, the impact of this approach on the rate of unnecessary activation of coronary catheterisation lab (CCL) remains unclear.

METHODS

The study reviewed consecutive STEMI patients over 3 years (July 2015 to June 2018) from all primary percutaneous coronary intervention (PPCI) centres and inter-hospital transfers (IHT) from non-PPCI capable centres in Western Australia. Out-of-hospital cardiac arrests (OOHCA) and STEMI calls for in-patients receiving treatment for other medical reasons were excluded.

RESULTS

During the 3 years study period, 1,736 STEMI cases were recorded. Pre-hospital (PH) activation occurred in 799 (46%) cases. Median door to balloon time (D2BT) was 68 minutes (IQR 63 mins). D2BT for PH activation (40 min [IQR 25 min]) was significantly lower than both the PPCI centre emergency department (ED) activation (86 min [IQR 55 min]) and IHT activation groups (108 min [IQR 55 min]), p-value <0.00001. In PH activation group 98% patients received primary PCI in less than 90 minutes compared to 54% and 26% patients in the ED and the IHT activation groups, respectively. False positive STEMI activation rate was lower in the PH activation group (2.75%) compared to ED activation (5.4%) and IHT group (6%), p-value 0.0115. The false positive rate did not vary significantly between working hours and out-of-hour calls (5% vs 4%, p-value=0.304). Pericarditis, coronary artery disease other than STEMI, atypical chest pain, and stress induced cardiomyopathy were the common diagnoses in false positive activations.

CONCLUSION

Pre-hospital activation of STEMI leads to reduced door to balloon times without a significant increase in inappropriate procedures, though false positive activation rates are unclear. The majority of STEMI patients transferred from non-PPCI centres failed to receive reperfusion therapy within 90 minutes of initial hospital presentation. Further studies are required to assess the benefits of thrombolysis in selected patients in inter-hospital transfer group.

Association of hypertension with mortality in patients hospitalised with COVID-19

Objective

To assess whether hypertension is an independent risk factor for mortality among patients hospitalised with COVID-19, and to evaluate the impact of ACE inhibitor and angiotensin receptor blocker (ARB) use on mortality in patients with a background of hypertension.

Method

This observational cohort study included all index hospitalisations with laboratory-proven COVID-19 aged ≥18 years across 21 Australian hospitals. Patients with suspected, but not laboratory-proven COVID-19, were excluded. Registry data were analysed for in-hospital mortality in patients with comorbidities including hypertension, and baseline treatment with ACE inhibitors or ARBs.

Results

546 consecutive patients (62.9±19.8 years old, 51.8% male) hospitalised with COVID-19 were enrolled. In the multivariable model, significant predictors of mortality were age (adjusted OR (aOR) 1.09, 95% CI 1.07 to 1.12, p<0.001), heart failure or cardiomyopathy (aOR 2.71, 95% CI 1.13 to 6.53, p=0.026), chronic kidney disease (aOR 2.33, 95% CI 1.02 to 5.32, p=0.044) and chronic obstructive pulmonary disease (aOR 2.27, 95% CI 1.06 to 4.85, p=0.035). Hypertension was the most prevalent comorbidity (49.5%) but was not independently associated with increased mortality (aOR 0.92, 95% CI 0.48 to 1.77, p=0.81). Among patients with hypertension, ACE inhibitor (aOR 1.37, 95% CI 0.61 to 3.08, p=0.61) and ARB (aOR 0.64, 95% CI 0.27 to 1.49, p=0.30) use was not associated with mortality.

Conclusions

In patients hospitalised with COVID-19, pre-existing hypertension was the most prevalent comorbidity but was not independently associated with mortality. Similarly, the baseline use of ACE inhibitors or ARBs had no independent association with in-hospital mortality.

Prehospital continuous positive airway pressure (CPAP) for acute respiratory distress: a randomised controlled trial

OBJECTIVE

To compare the efficacy of continuous positive airway pressure (CPAP) versus usual care for prehospital patients with severe respiratory distress.

METHODS

We conducted a parallel group, individual patient, non-blinded randomised controlled trial in Western Australia between March 2016 and December 2018. Eligible patients were aged ≥40 years with acute severe respiratory distress of non-traumatic origin and unresponsive to initial treatments by emergency medical service (EMS) paramedics. Patients were randomised (1:1) to usual care or usual care plus CPAP. The primary outcomes were change in dyspnoea score and change in RR at ED arrival, and hospital length of stay.

RESULTS

708 patients were randomly assigned (opaque sealed envelope) to usual care (n=346) or CPAP (n=362). Compared with usual care, patients randomised to CPAP had a greater reduction in dyspnoea scores (usual care -1.0, IQR -3.0 to 0.0 vs CPAP -3.5, IQR -5.2 to -2.0), median difference -2.0 (95% CI -2.5 to -1.6); and RR (usual care -4.0, IQR -9.0 to 0.0 min^-1 vs CPAP -8.0, IQR -14.0 to -4.0 min^-1), median difference -4.0 (95% CI -5.0 to -4.0) min^-1. There was no difference in hospital length of stay (usual care 4.2, IQR 2.1 to 7.8 days vs CPAP 4.8, IQR 2.5 to 7.9 days) for the n=624 cases admitted to hospital, median difference 0.36 (95% CI -0.17 to 0.90).

CONCLUSIONS

The use of prehospital CPAP by EMS paramedics reduced dyspnoea and tachypnoea in patients with acute respiratory distress but did not impact hospital length of stay.

TRIAL REGISTRATION NUMBER

ACTRN12615001180505.

A 5α-reductase (SRD5A2) polymorphism is associated with serum testosterone and sex hormone-binding globulin in men, while aromatase (CYP19A1) polymorphisms are associated with oestradiol and luteinizing hormone reciprocally

CONTEXT

Pituitary luteinizing hormone (LH) stimulates testicular production of testosterone (T) which is metabolized to dihydrotestosterone (DHT) by 5α-reductase and to oestradiol (E2) by aromatase. How the activity of population variants in these enzymes impacts on gonadal function is unclear. We examined whether polymorphisms in 5α-reductase (SRD5A2) and aromatase (CYP19A1) genes predict circulating sex hormone concentrations.

DESIGN

Cross-sectional analysis of 1865 community-dwelling men aged 50.4 ± 16.8 years.

MEASUREMENTS

Early morning sera assayed for T, DHT and E2 (mass spectrometry), and SHBG and LH (immunoassay). Two SRD5A2 and eleven CYP19A1 polymorphisms were analysed by PCR. Regression models were adjusted for age and cardiometabolic risk factors.

RESULTS

SRD5A2 polymorphism rs9282858 GA vs. GG was associated with higher serum T (+1.5 nmol/L, P < 0.001) and higher SHBG (+3.3 nmol/L, P = 0.001). CYP19A1 polymorphisms were associated with higher serum E2 and lower LH in reciprocal fashion, from which the two-copy haplotype rs10046 = T/rs2899470 = G/rs11575899 = I/rs700518 = G/rs17703883 = T was associated with higher E2 (63.4 vs. 56.5 pmol/L, P = 0.001) and lower LH (3.9 vs. 4.5 IU/L, P = 0.001) compared to null copies. Conversely, rs10046 = C/rs2899470 = T/rs11575899 = D/rs700518 = A/rs17703883 = C was associated with lower E2 (51.8 vs. 62.0 pmol/L, P = 0.001) and higher LH (5.7 vs. 3.9 IU/L, P < 0.001). These haplotypes were associated primarily with differences in E2 in men <65 years and LH in men ≥65 years.

CONCLUSIONS

A 5α-reductase polymorphism predicts circulating T and SHBG, while aromatase polymorphisms predict E2 and LH in reciprocal fashion. Age and aromatase polymorphisms interact to affect E2 and LH. How these functional polymorphisms impact on male reproductive and general health outcomes requires further study.

Ischaemic Stroke and the Echocardiographic "Bubble Study": Are We Screening the Right Patients?

BACKGROUND

Patent foramen ovale (PFO) is a potential mechanism for paradoxical embolism in cryptogenic ischaemic stroke or transient ischaemic attack (TIA). PFO is typically demonstrated with agitated saline ("bubble study", BS) during echocardiography. We hypothesised that the BS is frequently requested in patients that have a readily identifiable cause of stroke, that any PFO detected is likely incidental, and its detection often does not alter management.

METHODS

This was a retrospective observational study of patients with recent ischaemic stroke/TIA referred for a BS. Patient demographics, stroke risk factors, vascular/cerebral imaging results and transoesophageal echocardiogram (TOE) reports were recorded. A "modified" Risk of Paradoxical Embolism (RoPE) score was calculated. Change in management was defined as antiplatelet/anticoagulant therapy alteration or referral for PFO closure. Bubble Study complications were recorded.

RESULTS

Among 715 patients with ischaemic stroke/TIA referred for a BS, 8.7% had atrial fibrillation and 9.2% had carotid stenosis ≥70%. At least three stroke risk factors were present in 39.3% and only 47.1% of patients screened had a "modified" RoPE score of >5. A PFO was detected in 248 patients of whom only 31% (77/248) had a subsequent change in management. Of BS performed, 1/924 patients (0.1%) suffered a TIA as a complication.

CONCLUSIONS

The echocardiographic BS is frequently performed in patients that have a readily identifiable cause of stroke and whose PFO unlikely relates to the stroke/TIA. Bubble Study findings resulted in a change in management in the minority. The procedure is safe but the complication rate warrants informed consent.

Neutral associations of testosterone, dihydrotestosterone and estradiol with fatal and non-fatal cardiovascular events, and mortality in men aged 17-97 years

CONTEXT

Lower testosterone (T) is associated with poorer health outcomes in older men, however, the relationship between T, dihydrotestosterone (DHT) and estradiol (E2) with cardiovascular disease (CVD) in younger to middle-aged men remains unclear.

OBJECTIVES

We assessed associations between endogenous sex hormones with mortality (all-cause and CVD) and CVD events, in a cohort of men aged 17-97 years.

PARTICIPANTS AND METHODS

Sex hormones were assayed using mass spectrometry in 2143 men from the 1994/5 Busselton Health Survey. Outcomes to December 2010 were analysed.

RESULTS

Of the 1804 men included in the analysis, mean age was 50·3 ± 16·8 years and 68·9% of men were aged <60. Mean follow-up period was 14·9 years. There were 319 deaths, 141 CVD deaths and 399 CVD events. Compared to the full cohort, men who died had lower baseline T (12·0 ± 4·4 vs 13·6 ± 4·9 nmol/l), free T (181·9 ± 52·9 vs 218·3 ± 63·8 pmol/l) and DHT (1·65 ± 0·64 vs 1·70 ± 0·72 nmol/l), but higher E2 (64·0 ± 32 vs 60·1 ± 30·2 pmol/l). After adjustment for risk factors, T was not associated with mortality (adjusted HR = 0·90, 95% CI 0·79-1·04; P = 0·164 for every increase in 1 SD of T), CVD deaths (adjusted HR = 1·04, 95% CI 0·84-1·29; P = 0·708) or CVD events (adjusted HR = 1·03, 95% CI 0·92-1·15, P = 0·661). No associations were found for free T, DHT or E2. Results were similar for men older and younger than 60 years.

CONCLUSIONS

In predominantly middle-aged men, T, DHT and E2 do not influence mortality or CVD outcomes. This neutral association of hormones with CVD contrasts with prior studies of older men.

Epidemiological and Mendelian Randomization Studies of Dihydrotestosterone and Estradiol and Leukocyte Telomere Length in Men

CONTEXT

Advancing age is accompanied by an accumulation of ill health and shortening of chromosomal telomeres signifying biological aging. T is metabolized to DHT by 5α-reductase (SRD5A2) and to estradiol (E2) by aromatase (CYP19A1). Telomerase preserves telomeres, and T and E2 regulate telomerase expression and activity in vitro.

OBJECTIVE

The objective of the study was to establish whether circulating T or its metabolites, DHT or E2, and single-nucleotide polymorphisms in SRD5A2 or CYP19A1 associate with leucocyte telomere length (LTL) in men.

PARTICIPANTS AND METHODS

Early-morning serum T, DHT, and E2 were assayed using mass spectrometry, and SRD5A2 and CYP19A1 single-nucleotide polymorphisms and LTL analyzed by PCR in 980 men from the Western Australian Busselton Health Survey who participated in the study. LTL was expressed as the T/S ratio.

RESULTS

Men were aged (mean ± SD) 53.7 ± 15.6 years. LTL decreased linearly with age, from the T/S ratio of 1.89 ± 0.41 at younger than 30 years to 1.50 ± 0.49 at 70 to younger than 80 years (r = -0.225, P < .0001). After adjustment for age, DHT and E2 were positively correlated with LTL (DHT, r = 0.069, P = .030; E2, r = 0.068, P = .034). The SRD5A2 rs9282858 polymorphism was associated with serum DHT but not with LTL. Three dominant alleles of CYP19A1 were each associated with lower serum E2 and shorter LTL: rs2899470 T (E2, 59.3 vs 68.6 pmol/L, P < .0001; T/S ratio, 1.54 vs 1.62, P = .045), rs10046 C (60.5 vs 68.1 pmol/L, P = .0005, 1.54 vs 1.62, P = .035), and rs700518 A (59.9 vs 68.9 pmol/L, P < .0001, 1.54 vs 1.63, P = .020). A single-copy haplotype C/T/I/A/T rs10046/rs2899470/rs11575899/rs700518/rs17703883 (52% prevalence) was associated with both lower E2 and shorter LTL.

CONCLUSIONS

In men, serum DHT and E2 correlate with LTL independently of age. Aromatase gene polymorphisms include three dominant alleles that are associated with both lower serum E2 and shorter LTL. E2 influences telomere length in vivo, thus warranting further studies to examine whether hormonal interventions might slow biological aging in men.

Higher ferritin levels, but not serum iron or transferrin saturation, are associated with Type 2 diabetes mellitus in adult men and women free of genetic haemochromatosis

CONTEXT

Iron overload predisposes to diabetes and higher ferritin levels have been associated with diabetes. However, it is unclear whether ferritin reflects differences in iron-related parameters between diabetic and nondiabetic persons. We examined associations of serum ferritin, iron and transferrin saturation with Type 2 diabetes in adults without genetic predisposition to iron overload.

DESIGN, PARTICIPANTS AND MEASUREMENTS

Cross-sectional analysis of community-dwelling men and women aged 17-97 years from the Busselton Health Survey, Western Australia. Men and women carrying genotypes associated with haemochromatosis (C282Y/C282Y or C282Y/H63D) were excluded. Serum ferritin, iron and transferrin saturation were assayed.

RESULTS

There were 1834 men (122 with diabetes, 6·6%) and 2351 women (141 with diabetes, 6%). In men, higher serum ferritin was associated with diabetes after adjusting for age, smoking, alcohol, cardiovascular history, body mass index (BMI), waist, blood pressure, lipids, C-reactive protein (CRP), adiponectin, alanine transaminase (ALT) and gamma-glutamyl transpeptidase (GGT) [odds ratio (OR): 1·29 per 1 unit increase log ferritin, 95% confidence interval (CI) = 1·01-1·65, P = 0·043]. In women, higher serum ferritin was associated with diabetes [fully adjusted OR: 1·31 per 1 unit increase log ferritin, 95% CI = 1·04-1·63, P = 0·020; 1·84 for tertile (T) 3 vs T1, 95% CI = 1·09-3·11]. Neither iron levels nor transferrin saturation were associated with diabetes risk in men or women. Higher ferritin was not associated with insulin resistance in nondiabetic adults.

CONCLUSIONS

In adults, higher ferritin levels are independently associated with prevalent diabetes while iron and transferrin saturation are not. Ferritin is a robust biomarker for diabetes risk, but further investigation is needed to clarify whether this relationship is mediated via iron metabolism.

Testosterone, dihydrotestosterone and estradiol are differentially associated with carotid intima-media thickness and the presence of carotid plaque in men with and without coronary artery disease

Clarifying the relationship of sex hormones to preclinical atherosclerosis could illuminate pathways by which androgens are associated with cardiovascular events and mortality. Our aim was to determine hormone profiles associated with carotid intima-media thickness (CIMT) and carotid atheroma, in men with and without known coronary artery disease (CAD). We included 492 community-based men aged 20-70 years (Group A) and 426 men with angiographically proven CAD aged <60 years (Group B). Fasting early morning sera were assayed for testosterone (T), dihydrotestosterone (DHT) and estradiol (E2) using mass spectrometry. CIMT and carotid plaque were assessed ultrasonographically. Mean (±SD) age was Group A: 53.8±12.6 and Group B: 49.6±5.1 years. Higher T was associated with reduced CIMT (-0.011 mm per 1-SD increase, p=0.042) and lower prevalence of carotid plaque (odds ratio [OR] per 1-SD increase, 0.68, p=0.012) in Group A, but not B. E2 was associated with increased CIMT in Group A (0.013 mm, p=0.011) but not B. Higher DHT and E2 were associated with reduced carotid plaque in Group B (DHT: OR=0.77, p=0.024; E2: OR=0.75, p=0.008), but not A. In community-dwelling men, higher T is associated with favourable CIMT and lower prevalence of carotid plaque, while higher E2 is associated with worse CIMT. In men with CAD, higher DHT or E2 are associated with less carotid plaque. T, DHT and E2 are differentially associated with preclinical carotid atherosclerosis in a cardiovascular phenotype-specific manner. Interventional studies are needed to examine effects of exogenous T and its metabolites DHT and E2, on atherogenesis.

Differential associations of testosterone, dihydrotestosterone and oestradiol with physical, metabolic and health-related factors in community-dwelling men aged 17-97 years from the Busselton Health Survey

OBJECTIVES

Lower testosterone (T) levels are associated with poorer health outcomes in older men, but associations in younger or middle-aged men are uncertain, and data for dihydrotestosterone (DHT) and oestradiol (E2) are limited. We assessed the associations of circulating T, DHT and E2 with physical and health-related factors in a cohort comprising men aged 17-97 years.

PARTICIPANTS AND METHODS

Serum from 2143 community-dwelling men from the 1994/95 Busselton Health Survey was assayed for T, DHT and E2 using liquid chromatography-tandem mass spectrometry. Men receiving hormonal therapy or reporting the use of testosterone, or with prostate cancer or orchidectomy were excluded.

RESULTS

Of the men, 43% had never smoked, 6·1% had diabetes and 16·8% cardiovascular disease (CVD). Mean (±SD) age was 50·3 ± 17·0 years. Total T was moderately correlated with DHT (r = 0·56), E2 (r = 0·35) and sex hormone-binding globulin (r = 0·53). In age-, smoking-, body mass index (BMI)- and sex hormone-binding globulin (SHBG)-adjusted analyses, T was inversely associated with metabolic syndrome score, while DHT and E2 were not associated. In multivariable models, higher total T was associated with lower age, BMI and C-reactive protein, and with higher creatinine and haemoglobin, independently of SHBG. Higher DHT was associated with lower age, BMI and glucose level, and higher creatinine and haemoglobin. E2 was positively associated with age, BMI and haemoglobin.

CONCLUSIONS

In men spanning younger, middle and older ages, circulating androgens are more related to age and metabolic factors than CVD or chronic disease. Further investigation is required to clarify whether androgens and oestrogens have contrasting roles as risk predictors for CVD.

Body mass index and waist circumference: relationship to cardiometabolic risk factors in children--Busselton Health Study 2005-2007

AIM

This study aims to analyse the continuous relationship of each cardiometabolic risk factor with body mass index (BMI) and waist circumference percentiles in a population-based sample of children.

METHODS

A cross-sectional sample of 996 school children aged 6-16.9 years in Busselton, Western Australia, (2005-2007) had anthropometry and fasting blood tests for total cholesterol, high density lipoprotein, low density lipoprotein, triglycerides, glucose, insulin, high-sensitive C-reactive protein, liver function tests and adiponectin. Age- and menarche (for girls)-adjusted means of each risk factor were related to BMI and waist circumference centiles across the full normal-overweight-obese range.

RESULTS

The correlations between BMI and waist circumference (boys 0.91 and girls 0.91) and between BMI z-score and waist z-score (boys 0.80 and girls 0.82) were high. An increase in insulin across all centile groups (for BMI and waist circumference) was found in both sexes. An increase was found for diastolic blood pressure and systolic blood pressure z-score, high density lipoprotein, high-sensitive C-reactive protein, alanine transaminase and gamma-glutamyltransferase in only the centile groups >85% for BMI and waist circumference for both sexes. Mixed and sex-discordant results were found for triglycerides, adiponectin and glucose.

CONCLUSION

There are important differences in the relationships between increasing BMI/adiposity, and each comorbidity and these relationships can differ between boys and girls. This information has implications for screening and management of adiposity-related cardiometabolic risk factors in children and for public health initiatives to reduce future burden of cardiovascular disease.

Impact of voluntary folate fortification on plasma homocysteine and serum folate in Australia from 1995 to 2001: a population based cohort study

STUDY OBJECTIVE

To investigate the effect of the voluntary folate fortification policy in Australia on serum folate and total plasma homocysteine (tHcy) concentrations.

DESIGN

Population based cohort study.

SETTING

Perth, Western Australia.

PARTICIPANTS

Men and women aged 27 to 77 years (n = 468), who were originally randomly selected from the Perth electoral roll. The cohort was surveyed in 1995/96 before widespread introduction of folate fortification of a variety of foods, and followed up on two occasions, firstly in 1998/99 and again in 2001, when a moderate number of folate fortified foods were available. Subjects with abnormal serum creatinine concentrations at baseline were excluded from this analysis.

MAIN RESULTS

Repeated measures analysis of variance was used to determine changes in serum folate and tHcy over the three surveys and to assess whether time trends were related to age, sex, MTHFR C677T genotype, or consumption of folate fortified foods. An increase (38%) in mean serum folate (p < 0.0005) and a decrease (21%) in mean tHcy (p < 0.0005) were seen after introduction of the voluntary folate fortification policy in Australia. Serum folate was consistently higher (p = 0.032) and tHcy was consistently lower (p = 0.001) in subjects who consumed at least one folate fortified food compared with subjects who did not consume any folate fortified foods in the previous week. The time related changes in serum folate and tHcy were affected only by intake of folate fortified foods (p < 0.0005) and not by any other measured variables including age, sex, or MTHFR genotype.

CONCLUSION

Voluntary fortification of foods with folate in Australia has been followed by a substantial increase in serum folate and decrease in tHcy in the general population.

Effect of Atrial Septal Mobility on Transcatheter Closure of Interatrial Communications

BACKGROUND

Transcatheter techniques have evolved as alternatives to surgical closure of interatrial communications due to its less invasive nature and low morbidity. The technique may be limited by the inability to deploy the device and, thus, may be complicated by significant residual shunting. Mobile or redundant septal tissue has been implicated as a possible cause of unsuccessful closure.

METHODS

To determine if atrial septal hypermobility precludes successful transcatheter device closure of interatrial communications, 69 patients (mean age 46.4 +/- 17.5 years [male:female ratio 34:35]) with periprocedural transesophageal echocardiograms were reviewed. Septal excursion was defined as the maximal transit of the interatrial septum between either side of the plane connecting the superior and inferior attachment points. Unsuccessful closure was defined as subsequent cardiac surgery to close the defect, inability to deploy the device, recurrent attempts at closure, device malalignment, residual shunting greater than mild in degree on follow-up transthoracic study, and procedural complications.

RESULTS

Reasons for closure were the following: embolic events (n = 48); platypnea/orthodeoxia (n = 15); atrial septal defect with right ventricular dilatation and paroxysmal atrial tachycardia (n = 2); atrial septal defect (n = 3); and prophylactic patent foramen ovale closure in a scuba diver (n = 1). Successful closure occurred in 76% of patients (n = 53). Compared with those patients with successful transcatheter closure, the mean septal excursion in patients with failed closure was 0.66 +/- 0.56 cm versus 0.76 +/- 0.47 cm (P = not significant [NS]).

CONCLUSION

Our results do not support the concern that exaggerated septal mobility compromises successful device closure of interatrial communications.

Westernization of Chinese adults and increased subclinical atherosclerosis

Cardiovascular event rates are much lower in China compared with developed countries. "Westernization" of diet and lifestyle in the Chinese, however, may lead to an increased prevalence of atherosclerosis-related diseases. Because carotid intima-media thickness (IMT) is a marker of subclinical atherosclerosis, we examined IMT and vascular risk profile in community-based groups of rural Chinese, Westernized urban Chinese, and urban whites. Mean IMT of the common carotid artery was measured in 348 healthy adults, aged 42+/-13 years (range 21 to 71 years); 116 subjects from rural China, 116 urban Chinese subjects living in Hong Kong or in Australia, and 116 urban Caucasians living in Australia. These 3 groups were matched for age, sex, and cigarette smoke exposure. Urban Chinese subjects had slightly better risk factor profile (higher HDL-cholesterol and lower blood pressure) compared with rural Chinese subjects. Despite this, however, the mean IMT was lowest in rural Chinese (0.50+/-0.10 mm), intermediate in urban Chinese (0.56+/-0.12 mm), and highest in urban whites (0.64+/-0.13 mm) (P<0.001 for comparisons between all groups). These differences in IMT were not altered after adjustment for the major traditional cardiovascular risk factors (serum lipids, smoking, and blood pressure or for body mass index). The influence of vascular risk factors on atherosclerosis between urban versus rural Chinese subjects was studied by multivariate regression models and by comparing the steepness of regression slopes between risk factors and IMT in the subject groups. The effects of smoking, HDL-cholesterol, and triglycerides on IMT were significantly greater in the urban compared with the rural Chinese (P<0.01). These data suggest that Westernization of Chinese subjects is associated with greater susceptibility to the pro-atherogenic effects of traditional vascular risk factors, such as lipids and smoking, and with evidence of increased IMT as a marker of subclinical atherosclerosis.