Obesity in youth is not an independent predictor of carotid IMT in adulthood: The Cardiovascular Risk in Young Finns Study
Introduction
Obesity is associated with clustering of several risk factors for cardiovascular disease including dyslipidemia, elevated blood pressure and hyperinsulinemia already in children and adolescents [1], [2]. Being obese in early life may be associated with long-term adverse cardiovascular health effects, as the risk of morbidity and mortality from coronary heart disease is increased in adult subjects who have been obese in adolescence [3], [4]. Obesity tracks significantly from childhood to adulthood [5] and this may partly explain the relationship between childhood obesity and later cardiovascular disease.
The thickness of the common carotid intima–media (IMT) measured by ultrasound is a marker of structural subclinical atherosclerosis. Increased IMT correlates with cardiovascular risk factors and predicts future cardiovascular events [6], [7], [8]. We have previously shown in the Young Finns cohort that risk factors identified in adolescence predict increased IMT two decades later in adulthood independently of the adult risk factor status [9]. This suggests that risk factors operating in early life may be associated with permanent damage to the arterial wall [10]. In the present analysis, we have examined the association between childhood/adolescence obesity and adult IMT in detail. In particular, we have assessed how the association between body mass index (BMI) in youth and IMT in adulthood varies according to the age of BMI measurement and how obesity tracking patterns are associated with adult IMT.
Section snippets
Subjects
The Cardiovascular Risk in Young Finns Study is an on-going multicentre follow-up study of atherosclerosis precursors of Finnish children and adolescents. The first cross-sectional survey was conducted in 1980 [11]. Total sample size was 4320 children and adolescents in six age cohorts (aged 3, 6, 9, 12, 15 and 18 years). The subjects were randomly chosen from the national register. A total of 3596 subjects (83.2% of those invited) participated in 1980. In 2001, we re-examined these
Results
BMI measured in youth was significantly associated with BMI measured in adulthood. The correlation coefficients varied between r = 0.30 and 0.65 in the six age groups (all P < 0.001). Tracking was generally similar in both sexes.
The prevalence of adult obesity (BMI >30 kg/m2) was 12.3% (men 13.5%; women 11.4%). The prevalence increased by age, being 7.2% in 24-year olds and 15.9% in 39-year olds. Table 1 shows mean BMI levels in childhood and adulthood and the prevalence of obesity in adulthood
Discussion
Longitudinal studies from childhood to adulthood have suggested that being obese or overweight in early life may be associated with increased atherosclerosis, including increased carotid artery IMT [9], [14] and coronary calcification [15], as well as with increased morbidity and mortality from cardiovascular causes [3], [4]. These findings suggest that obesity may have long-term influences on the development of atherosclerosis. Alternatively, the relationship between childhood obesity and
Acknowledgements
This study was financially supported by the Academy of Finland (Grant No. 53392), the Social Insurance Institution of Finland, Ministry of Education, the Turku University Foundation, Special Federal Grants for the Turku University Hospital, the Juho Vainio Foundation, the Finnish Foundation of Cardiovascular Research, the Emil Aaltonen Foundation, the Finnish Medical Foundation and the Finnish Cultural Foundation.
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