Birth weight, childhood body mass index and risk of coronary heart disease in adults: combined historical cohort studies.
BACKGROUND
Low birth weight and high childhood body mass index (BMI) is each associated with an increased risk of coronary heart disease (CHD) in adult life. We studied individual and combined associations of birth weight and childhood BMI with the risk of CHD in adulthood.


RESULTS
Birth weight and BMI at age seven years were available in 216,771 Danish and Finnish individuals born 1924-1976. Linkage to national registers for hospitalization and causes of death identified 8,805 CHD events during up to 33 years of follow-up (median = 24 years) after age 25 years. Analyses were conducted with Cox regression based on restricted cubic splines. Using median birth weight of 3.4 kg as reference, a non-linear relation between birth weight and CHD was found. It was not significantly different between cohorts, or between men and women, nor was the association altered by childhood BMI. For birth weights below 3.4 kg, the risk of CHD increased linearly and reached 1.28 (95% confidence limits: 1.13 to 1.44) at 2 kg. Above 3.4 kg the association weakened, and from about 4 kg there was virtually no association. BMI at age seven years was strongly positively associated with the risk of CHD and the relation was not altered by birth weight. The excess risk in individuals with a birth weight of 2.5 kg and a BMI of 17.7 kg/m(2) at age seven years was 44% (95% CI: 30% to 59%) compared with individuals with median values of birth weight (3.4 kg) and BMI (15.3 kg/m(2)).


CONCLUSIONS
Birth weight and BMI at age seven years appeared independently associated with the risk of CHD in adulthood. From a public health perspective we suggest that particular attention should be paid to children with a birth weight below the average in combination with excess relative weight in childhood.
Institute of Preventive Medicine, Copenhagen University Hospital, Copenhagen, Denmark. lg@ipm.regionh.dk
Lise Geisler
LG
Andersen
Lars
L
Angquist
Johan G
JG
Eriksson
Tom
T
Forsen
Michael
M
Gamborg
Clive
C
Osmond
Jennifer L
JL
Baker
Thorkild I A
TI
Sørensen
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001724:Birth Weight / Q000502:physiology*; D015992:Body Mass Index; D002648:Child; D015331:Cohort Studies; D003327:Coronary Disease / Q000453:epidemiology / Q000209:etiology / Q000503:physiopathology*; D003718:Denmark / Q000453:epidemiology; D005260:Female; D005387:Finland / Q000453:epidemiology; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D008875:Middle Aged; D016016:Proportional Hazards Models; D012042:Registries / Q000706:statistics & numerical data; D018570:Risk Assessment / Q000379:methods / Q000706:statistics & numerical data; D012307:Risk Factors