The effect of age and NT-proBNP on the association of central obesity with 6-years cardiovascular mortality of middle-aged and elderly diabetic people: the population-based Casale Monferrato study.
BACKGROUND
Among people with type 2 diabetes the relationship between central obesity and cardiovascular mortality has not been definitely assessed. Moreover, NT-proBNP is negatively associated with central obesity, but no study has examined their combined effect on survival. We have examined these issues in a well-characterized population-based cohort.


RESULTS
Survival data of 2272 diabetic people recruited in 2000 who had no other chronic disease have been updated to 31 December 2006. NT-proBNP was measured in a subgroup of 1690 patients. Cox proportional hazards modeling was employed to estimate the independent associations between cardiovascular and all-cause mortality and waist circumference. Mean age was 67.9 years, 49.3% were men. Both age and NT-proBNP were negatively correlated with waist circumference (r = -0.11, p<0.001 and r = -0.07, p = 0.002). Out of 2272 subjects, 520 deaths (221 for CV mortality) occurred during a median follow-up of 5.4 years. Central obesity was not associated with CV mortality (hazard ratio, HR, adjusted for age, sex, diabetes duration, 1.14, 95% CI 0.86-1.52). NTproBNP was a negative confounder and age a strong modifier of this relationship (p for interaction<0.001): age<70 years, fully adjusted model HR = 3.52 (1.17-10.57) and age ≥70 years, HR = 0.80 (0.46-1.40). Respective HRs for all-cause mortality were 1.86 (1.03-3.32) and 0.73 (0.51-1.04).


CONCLUSIONS
In diabetic people aged 70 years and lower, central obesity was independently associated with increased cardiovascular mortality, independently of the negative effect of NT-proBNP. In contrast, no effect on 6-years survival was evident in diabetic people who have yet survived up to 70 years.
Dept. of Medical Sciences, University of Turin, Turin, Italy.
Graziella
G
Bruno
Dept. of Medical Sciences, University of Turin, Turin, Italy.
Federica
F
Barutta
Dept. of Medical Sciences, University of Turin, Turin, Italy.
Andrea
A
Landi
Dept. of Medical Sciences, University of Turin, Turin, Italy.
Paolo
P
Cavallo Perin
Dept. of Medical Sciences, University of Turin, Turin, Italy.
Gabriella
G
Gruden
D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D002318:Cardiovascular Diseases / Q000150:complications* / Q000401:mortality; D002423:Cause of Death; D015897:Comorbidity; D003924:Diabetes Mellitus, Type 2 / Q000150:complications*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D020097:Natriuretic Peptide, Brain / Q000009:adverse effects*; D056128:Obesity, Abdominal / Q000150:complications* / Q000453:epidemiology*; D010446:Peptide Fragments / Q000009:adverse effects*; D011159:Population Surveillance; D015995:Prevalence; D012307:Risk Factors
D010446:Peptide Fragments; C109794:pro-brain natriuretic peptide (1-76); D020097:Natriuretic Peptide, Brain