obese childNew research presented at this year’s European Obesity Summit shows that a high body mass index (BMI) in childhood, and also gains in BMI, are associated with an increased risk of early stroke in adults for both men and women.
Adult body mass index (BMI) is associated with ischemic stroke, especially at younger ages, but the association between childhood BMI and ischemic stroke in adulthood is unclear. The authors aimed to investigate if childhood BMI and gain in BMI during childhood are associated with the risk of early and late adult ischemic stroke.
They studied a cohort of 307,677 Danish school children born from 1930 to 1987 who had weight and height measurements taken at age 7 through 13 years. BMI was calculated (kg/m2) and transformed to z-scores, a method for comparing how large a child is compared to a reference population. They then identified ischemic stroke events by linkage to national registers and categorised them as early (25 – 55 years) or late (>55 years) events. The effects of BMI and gain in BMI between ages 7 and 13 years were estimated.
During a total of 8,128,058 person-years of follow-up, 3,529 women and 5,370 men had an ischemic stroke. The authors found both men and women with a childhood BMI z-score above average had an increased risk of early, but not late, ischemic stroke. The pattern of the associations with early ischemic stroke were similar at all ages in childhood, but strongest at age 13 years, where a BMI z-score of 1 increased the risk of early stroke by 26% in women and 21% in men.
To put this in perspective, compared to an average height and weight child born in the late 1950s (girl: 156.7 cm and 44.6 kg, boy: 154.5 cm, 42.5 kg), a girl of the same height but who weighed 6.8 kg more would have an 26% higher risk of early ischemic stroke, and a boy of the same height who weighed 5.9 kg more would have a 21% higher risk of early ischemic stroke. A BMI z-score gain of 0.5 from age 7 to 13 years was also associated with an about 10% increased risk of early ischemic stroke in both women and men.
The authors say: “In this large prospective study we found that having a BMI above average in childhood as well as a BMI gain during childhood increases the risk of early adult ischemic stroke. Future research should address pathways through which these risks arise.”
They add: “The results of this study highlight the potential effects that childhood overweight and obesity on the early development of atherosclerosis as well as other factors such as hypertension and type 2 diabetes, which are risk factors for ischemic stroke.”
The authors are now planning to investigate the impact of body size (both height and BMI) on haemorrhagic stroke (which is a different form of stroke).