Impact of body mass index and diabetes on myocardial fat content, interstitial fibrosis and function.

PURPOSE: We hypothesize that both increased myocardial steatosis and interstitial fibrosis contributes to subclinical myocardial dysfunction in patients with increased body mass index and diabetes mellitus. BACKGROUND: Increased body weight and diabetes mellitus are both individually associated with a higher incidence of heart failure with preserved ejection fraction. However, it is unclear how increased myocardial steatosis and interstitial fibrosis interact to influence myocardial composition and function. METHODS: A total of 100 subjects (27 healthy lean volunteers, 21 healthy but overweight volunteers, and 52 asymptomatic overweight patients with diabetes) were prospectively recruited to measure left ventricular (LV) myocardial steatosis (LV-myoFat) and interstitial fibrosis (by extracellular volume [ECV]) using magnetic resonance imaging, and then used to determine their combined impact on LV global longitudinal strain (GLS) analysis by 2-dimensional (2D) speckle tracking echocardiography on the same day. RESULTS: On multivariable analysis, both increased body mass index and diabetes were independently associated with increased LV-myoFat. In turn, increased LV-myoFat was independently associated with increased LV ECV. Both increased LV-myoFat and LV ECV were independently associated with impaired 2D LV GLS. CONCLUSION: Patients with increased body weight and patients with diabetes display excessive myocardial steatosis, which is related to a greater burden of myocardial interstitial fibrosis. LV myocardial contractile function was determined by both the extent of myocardial steatosis and interstitial fibrosis, and was independent of increasing age. Further study is warranted to determine how weight loss and improved diabetes management can improve myocardial composition and function.

Lifestyle correlates of dietary patterns among young adults: evidence from an Australian birth cohort.

OBJECTIVE: Previous studies of sociodemographic and lifestyle correlates of dietary patterns among young adults have primarily focused on physical activity and smoking, with inconclusive results. This study aims to examine the associations between a broader range of lifestyles of young adults and their patterns of food consumption. DESIGN: Cross-sectional. SETTING: Brisbane, Australia. PARTICIPANTS: The data set are from a long running birth cohort study which commenced in 1981. Details of dietary intake and sociodemographic and lifestyle factors were from the 21-year follow-up of the Mater-University of Queensland Study of Pregnancy (MUSP) birth cohort. The effective cohort (n 2665, 57 % women) is of young adult offspring. Usual dietary intake was assessed using a Food Frequency Questionnaire (FFQ). Data on sociodemographic and lifestyle variables were obtained from self-reports. RESULTS: Western and prudent dietary patterns were identified for the combined cohort of women and men using principal components analysis. Multivariable linear regression models were used to examine the associations between lifestyle variables and dietary patterns adjusting for potential confounders. Results from multivariable adjusted models showed that physical activity, watching TV and smoking were strongly associated with each dietary pattern; alcohol consumption and BMI showed weaker associations (P < 0·05 for all). CONCLUSIONS: Our study describes a clustering of unhealthy lifestyles in young adults. Young adults with unhealthy lifestyles less often adhere to a healthy prudent dietary pattern and more often an unhealthy Western pattern. Dietary preferences are enmeshed in a lifestyle matrix which includes physical activity, sedentary activity, smoking and alcohol consumption of young adults.