The relationship of fatness, fitness, physical activity and sedentary behaviour with vascular health in human populations

Background: Impaired arterial structure and stiffness are strong predictors of cardiovascular events and mortality. These subclinical signs of impairment can be used to identify early stages of cardiovascular disease. Improved understanding of their determinants may enable earlier interventions to reduce cardiovascular risk. Aim: This research aimed to study the associations of fatness, fitness, physical activity and sedentary behaviour with arterial structure and stiffness. Methods: Data were from four large population-based studies: the Burnie Take Heart (BTH), Can Tho (CT), Childhood Determinants of Adult Health (CDAH), and Cardiovascular Risk in Young Finns (Young Finns) studies. The subjects for BTH (n=832 Australians aged 25‚Äö-64 years in 1998‚Äö-99), CT (n=1978 Vietnamese aged 25‚Äö-64 years in 2005), CDAH (n=2328 Australians aged 7‚Äö-15 years in 1985 and when aged 26‚Äö-36 years in 2004‚Äö-06) and Young Finns (n=2175 Finns aged 30‚Äö-45 years in 2007) were all drawn from population-based samples. Measurements included anthropometry, blood pressure, resting heart rate (RHR), physical activity and fitness, sedentary behaviours, blood biochemistry, and arterial structure and stiffness assessed using carotid ultrasound. Results: First, body mass index was positively associated with pulse pressure (an indicator of large artery stiffness) among adult Caucasians, but with both systolic and diastolic pressure among adult Asians. Second, adult carotid artery stiffness was exclusively dependent on adult body size and fatness, whereas adult carotid artery structure (assessed as intima-media thickness) was associated with childhood body size and fatness independently of attained adult values. Cross-sectional data showed that adult carotid artery stiffness was associated thirdly with physical fitness and fourthly with vigorous activity, each independently of current body size/fatness and with each association mediated by RHR. Fifth, carotid artery stiffness was positively associated with sitting time, independently of physical activity and fitness, body size/fatness, RHR, or metabolic syndrome. Conclusions: For the first time, our findings suggest a different pathophysiology related to obesity-induced hypertension among Caucasians (increased arterial stiffness phenotype) and Asians (essential hypertension phenotype). Adult arterial stiffness was primarily influenced by attained adult body size and fatness, whereas adult arterial structure was influenced by body size and fatness in both childhood and adulthood. Independently of fatness, young adults may reduce stiffening of large arteries by doing vigorous activity and improving their fitness,