Leptin and coronary heart disease: prospective study and systematic review.
OBJECTIVE
This study sought to better determine the link between leptin and coronary heart disease (CHD).


BACKGROUND
Circulating leptin is considered a risk factor for CHD but larger studies are needed.


METHODS
Leptin levels were measured in 550 men with fatal CHD or nonfatal myocardial infarction and in 1,184 controls nested within a prospective study of 5,661 British men and set in context with a meta-analysis.


RESULTS
Baseline leptin correlated with body mass index (BMI), blood pressure, total cholesterol, triglyceride, and inflammatory markers; correlations persisted after BMI adjustment. The within-person consistency of leptin values over 4 years (correlation coefficient: 0.79; 95% confidence interval [CI]: 0.73 to 0.83) was higher than those of some established cardiovascular risk factors. In a comparison of individuals in the top third with those in the bottom third of baseline leptin, the age- and town-adjusted odds ratio for CHD was 1.25 (95% CI: 0.96 to 1.62), decreasing to 0.98 (95% CI: 0.72 to 1.34) after adjustment for BMI. A systematic review identified 7 prospective reports with heterogeneous findings (I(2) = 60%, 13% to 82%). The combined adjusted risk ratio across all studies was 1.44 (95% CI: 0.95 to 2.16) in a comparison of extreme thirds of leptin levels. The inconsistency between studies was partially explained by sample size, with combined estimates from studies involving >100 CHD cases (1.28, 95% CI: 0.80 to 2.04) being somewhat weaker than those from smaller studies (1.81, 95% CI: 0.76 to 4.31).


CONCLUSIONS
Previous studies appear to have overestimated associations of leptin and CHD risk. Our results suggest a moderate association that is largely dependent on BMI.
Sattar
Naveed
N
BHF Glasgow Cardiovascular Research Centre, Faculty of Medicine, University of Glasgow, Glasgow, Scotland, UK. nsattar@clinmed.gla.ac.uk
Wannamethee
Goya
G
Sarwar
Nadeem
N
Chernova
Julia
J
Lawlor
Debbie A
DA
Kelly
Anne
A
Wallace
A Michael
AM
Danesh
John
J
Whincup
Peter H
PH
D001794:Blood Pressure; D015992:Body Mass Index; D016022:Case-Control Studies; D002784:Cholesterol / Q000097:blood; D003327:Coronary Disease / Q000097:blood*; D005260:Female; D006801:Humans; D020738:Leptin / Q000097:blood*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011897:Random Allocation; D012307:Risk Factors; D014280:Triglycerides / Q000097:blood
D020738:Leptin; D014280:Triglycerides; D002784:Cholesterol