Metabolic syndrome and risk of mortality in middle-aged versus elderly individuals: the Nord-Trøndelag Health Study (HUNT).
OBJECTIVE
Recent reviews indicate that the metabolic syndrome is a risk factor for cardiovascular disease and mortality, but evidence is scarce in elderly individuals. We therefore examined the relationship between the metabolic syndrome and mortality rates among individuals aged 40-59, 60-74 and 75-89 years. We also examined whether the syndrome was associated with mortality rates over and above the Framingham risk score.


METHODS
We studied prospectively 6,748 men and women who participated in the Nord-Trøndelag Health Study, Norway, from 1995 to 1997 (HUNT 2) and defined the metabolic syndrome by the International Diabetes Federation criteria.


RESULTS
During 53,617 person-years of follow-up (mean per person, 7.9 years), 955 individuals died, of whom 585 died from cardiovascular disease. Among individuals who were 40-59 years of age at baseline, the presence of the metabolic syndrome was associated with increased relative risk of cardiovascular and total mortality (age- and sex-adjusted hazard ratios 3.97 [95% CI: 2.00-7.88] and 2.06 [1.35-3.13], respectively, equivalent to population-attributable risks of 20.7 and 14.2%, respectively). The Framingham risk score accounted for less than one-third of the effect of metabolic syndrome on mortality rates. After the age of 60 years, the metabolic syndrome was not associated with increased mortality rates. We found a significant interaction between the metabolic syndrome and age on the relative risk of mortality. Results were confirmed in a sub-sample without cardiovascular disease at baseline.


CONCLUSIONS
The metabolic syndrome is a risk factor for mortality, over and above the Framingham risk score, in middle-aged, but not in elderly individuals.
Hildrum
B
B
Department of Psychiatry, Nord-Trøndelag Hospital Trust, Namsos Hospital, 7800, Namsos, Norway. bjorn.hildrum@hnt.no
Mykletun
A
A
Dahl
A A
AA
Midthjell
K
K
D000368:Aged; D000959:Antihypertensive Agents / Q000627:therapeutic use; D001786:Blood Glucose / Q000378:metabolism; D001794:Blood Pressure; D002318:Cardiovascular Diseases / Q000401:mortality; D002784:Cholesterol / Q000097:blood; D008076:Cholesterol, HDL / Q000097:blood; D048909:Diabetes Complications / Q000097:blood / Q000188:drug therapy / Q000401:mortality; D003925:Diabetic Angiopathies / Q000097:blood / Q000453:epidemiology / Q000401:mortality; D005260:Female; D006801:Humans; D007004:Hypoglycemic Agents / Q000627:therapeutic use; D008297:Male; D024821:Metabolic Syndrome / Q000150:complications / Q000453:epidemiology* / Q000401:mortality*; D008875:Middle Aged; D009664:Norway / Q000453:epidemiology; D018570:Risk Assessment; D014280:Triglycerides / Q000097:blood
D000959:Antihypertensive Agents; D001786:Blood Glucose; D008076:Cholesterol, HDL; D007004:Hypoglycemic Agents; D014280:Triglycerides; D002784:Cholesterol