Body mass index, abdominal fatness, fat mass and the risk of atrial fibrillation: a systematic review and dose-response meta-analysis of prospective studies

Association of Weight Fluctuation With Mortality in Japanese Adults

IMPORTANCE

Weight cycling is associated with the risk of mortality from heart disease, but many studies have not distinguished between simple nonlinear (monotone) weight changes and more complex changes that reflect fluctuations.

OBJECTIVE

To assess whether extreme body weight variation is associated with mortality after controlling for nonlinear weight changes.

DESIGN, SETTING, AND PARTICIPANTS

In this prospective clinical cohort study, 4796 Japanese atomic bomb survivors were examined in the clinic as part of a biennial health examination and research program. The study consisted of a 20-year longitudinal baseline period (July 1, 1958, to June 30, 1978) and subsequent mortality follow-up of 27 years (July 1, 1978, to June 30, 2005) Participants were initially between the ages of 20 and 49 years during the baseline period and, throughout the baseline period, had no diagnoses of cardiovascular disease (CVD) or cancer and attended at least 7 of 10 scheduled examinations. Data analysis was performed from October 16, 2015, to May 13, 2016.

EXPOSURES

Residual variability in body mass index (BMI) during the baseline period.

MAIN OUTCOMES AND MEASURES

Outcomes were mortality from ischemic heart disease, cerebrovascular disease, other CVDs combined, other causes (except cancer), and cancer. Root mean squared error was calculated to capture individual residual variation in BMI after adjustment for baseline BMI trends, and the association of magnitude of residual variation with mortality was calculated as relative risk.

RESULTS

In total, 4796 persons (mean [SD] age, 35.0 [7.3] years at first baseline examination; 3252 [67.8%] female; mean [SD] BMI, 21.2 [2.8] at first baseline visit [20.6 (2.4) among men and 21.5 (2.9) among women]) participated in the study. During follow-up, 1550 participants died: 82 (5.3% of all deaths) of ischemic heart disease, 181 (11.7%) of cerebrovascular disease, 186 (12.0%) of other CVDs, 615 (39.7%) of cancer, and 486 (31.3%) of other causes. Magnitude of residual variation in weight was associated with all-cause mortality (relative risk, 1.25 for 1 U of additional variation; 95% CI, 1.06-1.47) and ischemic heart disease mortality (relative risk, 2.49; 95% CI, 1.41-4.38).

CONCLUSIONS AND RELEVANCE

The findings suggest that an association exists between weight variation and heart disease mortality and that weight loss interventions, if deemed to be necessary, should be considered carefully.

Assessment of the validity of multiple obesity indices compared with obesity-related co-morbidities

Objective

The aim of the present study was to compare selected obesity indicators with comprehensive health status.

Design

The study employed a pooled cross-sectional design.

Setting

BMI, waist circumference, waist-to-height ratio (WHtR) and body fat percentage were considered as indirect obesity indicators. The Edmonton Obesity Staging System (EOSS) was used as a composite indicator to comprehensively reflect obesity-related co-morbidities. Cohen’s κ coefficient was used to evaluate inter-measurement agreement for obesity. Conformity of indirect obesity indicators to the EOSS was assessed based on percentage agreement (proportion classified as obese and severely unhealthy as a result of obesity among the total sample), sensitivity (proportion classified as obese among individuals severely unhealthy as a result of obesity) and specificity (proportion classified as non-obese among fairly healthy individuals). Logistic regression analysis was used to identify the sociodemographic factors most strongly associated with conformity.

Participants

The study included 17338 adults from the Korea National Health and Nutrition Examination survey conducted between July 2008 and May 2011.

Results

Level of conformity to the EOSS was highest for WHtR (60·77 %) and lowest for BMI (35·96 %). WHtR and BMI had the highest sensitivity (53·7 %) and specificity (98·4 %), respectively. Predictability of conformity was lower among men for all indirect obesity indicators.

Conclusions

WHtR has the greatest potential to identify individuals at risk of health problems due to obesity. Individual demographic factors must be considered in selecting the most appropriate obesity measurement.

Metabolically Healthy Obesity and Risk for Atrial Fibrillation: The HUNT Study

OBJECTIVE

Atrial fibrillation (AF) is the most common arrhythmia and has been described as a global epidemic. Although AF is associated with both obesity and its metabolic consequences, little is known about the association between metabolically healthy obesity and AF.

METHODS

In a population-based study, 47,870 adults were followed for incident AF from 2006 to 2008 until 2015. Participants were classified according to BMI and metabolic status (using waist circumference, triglycerides, high-density lipoprotein cholesterol, blood pressure, and glucose) at baseline.

RESULTS

During a median follow-up of 8.1 years, 1,758 participants developed AF. Compared with metabolically healthy individuals with BMI < 25 kg/m² , the multivariable-adjusted hazard ratios for metabolically healthy and unhealthy obesity were 1.6 (95% CI: 1.2 to 2.1) and 1.6 (95% CI: 1.3 to 1.9), respectively. AF risk increased according to the severity of obesity.

CONCLUSIONS

Metabolically healthy and unhealthy obesity increased AF risk to a similar extent. Severity of obesity was positively associated with AF risk regardless of metabolic status.

Usefulness of Epicardial Adipose Tissue Volume to Predict Recurrent Atrial Fibrillation After Radiofrequency Catheter Ablation

Although increasing evidence suggests that epicardial adipose tissue volume (EATV) is associated with post-ablation atrial fibrillation (AF), ranges of EATV predictive of post-ablation recurrence of AF remain unclear. In this study, we evaluated: (1) relationships between EATV and characteristics of AF, (2) impact of EATV on recurrent AF after radiofrequency ablation; , and (3) cut-off point for recurrent AF using a receiver operating characteristic curve. In 218 consecutive symptomatic patients undergoing who underwent ablation for AF (143 paroxysmal AF; 78 persistent AF), the EATV index (EATVI: EATV/body surface area, mL/m²) was measured using 320-row multidetector computed tomography. The high EATV group showed specific cardiometabolic derangements as well as left atrial dilatation and left ventricular dysfunction. Multivariate regression analysis showed that the EATVI was an independent predictor of recurrent AF after catheter ablation. High EATV (EATVI ≥ 85 mL/m²) or EATVI cutoff ≥116 mL/m² can predict recurrent AF after catheter ablation, independent of other risk factors. In conclusion, EATVI was an independent predictor of recurrent AF after catheter ablation; a high EATV tertile or EATVI cutoff may be useful for prediction of recurrent AF after catheter ablation. Future studies should determine the utility of the EATVI in the clinical setting of AF ablation.

Diabetes mellitus, blood glucose and the risk of heart failure: A systematic review and meta-analysis of prospective studies

BACKGROUND AND AIM

The strength of the association between diabetes and risk of heart failure has differed between previous studies and the available studies have not been summarized in a meta-analysis. We therefore quantified the association between diabetes and blood glucose and heart failure in a systematic review and meta-analysis.

METHODS AND RESULTS

PubMed and Embase databases were searched up to May 3rd 2018. Prospective studies on diabetes mellitus or blood glucose and heart failure risk were included. A random effects model was used to calculate summary relative risks (RRs) and 95% confidence intervals (CIs). Seventy seven studies were included. Among the population-based prospective studies, the summary RR for individuals with diabetes vs. no diabetes was 2.06 (95% CIs: 1.73-2.46, I² = 99.8%, n = 30 studies, 401495 cases, 21416780 participants). The summary RR was 1.23 (95% CI: 1.15-1.32, I² = 78.2%, n = 10, 5344 cases, 91758 participants) per 20 mg/dl increase in blood glucose and there was evidence of a J-shaped association with nadir around 90 mg/dl and increased risk even within the pre-diabetic blood glucose range. Among the patient-based studies the summary RR was 1.69 (95% CI: 1.57-1.81, I² = 85.5%, p_{heterogeneity}<0.0001) for diabetes vs. no diabetes (n = 41, 100284 cases and >613925 participants) and 1.25 (95% CI: 0.89-1.75, I² = 95.6%, p_{heterogeneity}<0.0001) per 20 mg/dl increase in blood glucose (1016 cases, 34309 participants, n = 2). In the analyses of diabetes and heart failure there was low or no heterogeneity among the population-based studies that adjusted for alcohol intake and physical activity and among the patient-based studies there was no heterogeneity among studies with ≥10 years follow-up.

CONCLUSIONS

These results suggest that individuals with diabetes are at an increased risk of developing heart failure and there is evidence of increased risk even within the pre-diabetic range of blood glucose.

Body mass index, abdominal fatness, and the risk of sudden cardiac death: a systematic review and dose-response meta-analysis of prospective studies

Although overweight and obesity are established risk factors for some types of heart disease including ischemic heart disease, heart failure and atrial fibrillation, less is known about the association between adiposity and sudden cardiac death. We conducted a systematic review and meta-analysis of prospective studies to clarify the association between adiposity and risk of sudden cardiac death. PubMed and Embase databases were searched up to July 20th 2017. Summary relative risks (RRs) and 95% confidence intervals (CIs) were calculated using random effects models. The summary RR was 1.16 (95% CI 1.05-1.28, I2 = 68%, n = 14) per 5 unit increment in BMI, and 1.82 (95% CI 1.61-2.07, I2 = 0%, n = 3) per 0.1 unit increase in waist-to-hip ratio, and 1.03 (95% CI 0.93-1.15, I2 = 0%, n = 2) per 10 cm increase in waist circumference. The heterogeneity in the analysis of BMI and sudden cardiac death persisted across most subgroup analyses. The association was stronger among studies with longer follow-up compared to short follow-up and was observed in the European and American studies, but not in the Asian studies. There was a J-shaped association between BMI and sudden cardiac death and the lowest risk was observed in the normal weight range, however, the increased risk with a low BMI was attenuated among studies with a longer duration of follow-up. This meta-analysis suggest an increased risk of sudden cardiac death with increasing BMI and waist-to-hip ratio, however, further studies with stratification for smoking status are needed of waist circumference, weight changes and adiposity at younger ages.

Physical activity modifies the risk of atrial fibrillation in obese individuals: The HUNT3 study

Background

Atrial fibrillation is the most common heart rhythm disorder, and high body mass index is a well-established risk factor for atrial fibrillation. The objective of this study was to examine the associations of physical activity and body mass index and risk of atrial fibrillation, and the modifying role of physical activity on the association between body mass index and atrial fibrillation.

Design

The design was a prospective cohort study.

Methods

This study followed 43,602 men and women from the HUNT3 study in 2006–2008 until first atrial fibrillation diagnosis or end of follow-up in 2015. Atrial fibrillation diagnoses were collected from hospital registers and validated by medical doctors. Cox proportional hazard regression analysis was performed to assess the association between physical activity, body mass index and atrial fibrillation.

Results

During a mean follow-up of 8.1 years (352,770 person-years), 1459 cases of atrial fibrillation were detected (4.1 events per 1000 person-years). Increasing levels of physical activity were associated with gradually lower risk of atrial fibrillation ( p trend 0.069). Overweight and obesity were associated with an 18% (hazard ratio 1.18, 95% confidence interval 1.03–1.35) and 59% (hazard ratio 1.59, 95% confidence interval 1.37–1.84) increased risk of atrial fibrillation, respectively. High levels of physical activity attenuated some of the higher atrial fibrillation risk in obese individuals (hazard ratio 1.53, 95% confidence interval 1.03–2.28 in active and 1.96, 95% confidence interval 1.44–2.67 in inactive) compared to normal weight active individuals.

Conclusion

Overweight and obesity were associated with increased risk of atrial fibrillation. Physical activity offsets some, but not all, atrial fibrillation risk associated with obesity.

The Impact of Bariatric Surgery on Sleep Disordered Breathing Parameters From Overnight Polysomnography and Home Sleep Apnea Test

Background Obstructive sleep apnea (OSA) is a common sleep disorder, especially in patients with obesity. Bariatric surgery is an effective tool to reduce weight and treat co-morbid diseases in patients with morbid obesity. One of these disorders is OSA. The most common bariatric procedures currently performed are Roux-en-Y gastric bypass (RYGB) and laparoscopic sleeve gastrectomy (LSG). Objectives Our study demonstrates that bariatric surgery is a very effective tool to reduce the severity of OSA, if not resolve it. Methods The medical charts of nine patients who had OSA and underwent bariatric surgery (LSG or RYGB) were reviewed and the apnea-hypopnea index (AHI) was compared before and after surgery. The study was conducted at the Sanford sleep center which is affiliated with the University of North Dakota School of Medicine. Results One patient was excluded from the statistical analysis since he was the only male patient, the remaining nine female patients had a significant reduction in AHI after surgery. The mean AHI before surgery was 40 events per hour and seven events per hour after surgery (P 0.004). The mean follow-up with sleep study after surgery was 16 months. The mean reduction in AHI was 80%. There was also an improvement in oxygen saturation (SpO2) before and after surgery (90% and 94% respectively, P 0.008). Conclusion The study confirms the significant reduction in AHI after bariatric surgery in female patients with OSA especially short term (one to two years postoperatively).

Diabetes mellitus, blood glucose and the risk of atrial fibrillation: A systematic review and meta-analysis of cohort studies

BACKGROUND

Diabetes and elevated blood glucose have been associated with increased risk of atrial fibrillation in a number of epidemiological studies, however, the findings have not been entirely consistent. We conducted a systematic review and meta-analysis to clarify the association.

MATERIAL AND METHODS

We searched the PubMed and Embase databases for studies of diabetes and blood glucose and atrial fibrillation up to July 18th 2017. Cohort studies were included if they reported relative risk (RR) estimates and 95% confidence intervals (CIs) of atrial fibrillation associated with a diabetes diagnosis, prediabetes or blood glucose. Summary RRs were estimated using a random effects model.

RESULTS

Thirty four studies were included in the meta-analysis of diabetes, pre-diabetes or blood glucose and atrial fibrillation. Thirty two cohort studies (464,229 cases, >10,244,043 participants) were included in the analysis of diabetes mellitus and atrial fibrillation. The summary RR for patients with diabetes mellitus versus patients without diabetes was 1.30 (95% CIs: 1.03-1.66), however, there was extreme heterogeneity, I² = 99.9%) and evidence of publication bias with Begg's test, p < 0.0001. After excluding a very large and outlying study the summary RR was 1.28 (95% CI: 1.22-1.35, I² = 90%, n = 31, 249,772 cases, 10,244,043 participants). The heterogeneity was mainly due to differences in the size of the association between studies and the results persisted in a number of subgroup and sensitivity analyses. The summary RR was 1.20 (95% CI: 1.03-1.39, I² = 30%, n = 4, 2392 cases, 58,547 participants) for the association between prediabetes and atrial fibrillation. The summary RR was 1.11 (95% CI: 1.04-1.18, I² = 61%, n = 4) per 20 mg/dl increase of blood glucose in relation to atrial fibrillation (3385 cases, 247,447 participants) and there was no evidence of nonlinearity, p_nonlinearity = 0.34.

CONCLUSIONS

This meta-analysis suggest that prediabetes and diabetes increase the risk of atrial fibrillation by 20% and 28%, respectively, and there is a dose-response relationship between increasing blood glucose and atrial fibrillation. Any further studies should clarify whether the association between diabetes and blood glucose and atrial fibrillation is independent of adiposity.

Sex Differences in the Impact of Body Mass Index on the Risk of Future Atrial Fibrillation: Insights From the Longitudinal Population-Based Tromsø Study

Background

Atrial fibrillation (AF) prevalence is increasing, and body mass index (BMI) is a risk factor for AF. However, sex differences in the impact of BMI on AF risk have not been fully elucidated.

Methods and Results

Data from the fourth survey (1994–1995) of the Tromsø Study (Norway) were used to investigate the association of single‐measurement BMI on future AF risk. To analyze the influence of BMI changes on AF risk, data from individuals who attended the third and fourth study surveys were used. AF diagnosis was derived from record linkage and end point adjudication. Cox regression analysis was conducted using fractional polynomials of BMI and BMI change with models adjusted for age, baseline BMI (change analyses), risk factors, comorbidities, and antihypertensive medications.

Data were available for 24 799 individuals from the fourth survey (mean age, 45.5±14.2 years; 52.9% women). Over 15.7±5.5 years, 811 women (6.2%) and 918 men (7.9%) developed AF. In men, lower BMI decreased AF risk and higher BMI increased risk (hazard ratios [95% confidence intervals] for BMI 18 or 40 kg/m² compared with 23 kg/m² were 0.75 [0.70–0.81] and 4.42 [3.00–6.53], respectively). The same pattern was identified in women. Two surveys were attended by 14 652 individuals. In men and women, a decrease in BMI over time was associated with decreased AF risk and an increase in BMI was associated with increased AF risk.

Conclusions

Within a population cohort, BMI was positively associated with AF risk. Change in BMI over time influenced AF risk in both men and women.