Associations of metabolic syndrome and C-reactive protein with mortality from total cancer, obesity-linked cancers and breast cancer among women in NHANES III

Although metabolic syndrome (MetS) is a prognostic factor for cancer occurrence, the association of MetS and cancer mortality remains unclear. The purpose of this study was to evaluate whether MetS, components of MetS and C-reactive protein (CRP) are associated with cancer mortality in women. A total of 400 cancer deaths, with 140 deaths from obesity-linked-cancers (OLCas), [breast (BCa), colorectal, pancreatic and endometrial], linked through the National Death Index, were identified from 10,104 eligible subjects aged 18 years. Cox proportional hazards regression was used to estimate multivariable-adjusted hazard ratios (HR) for cancer mortality. MetS was associated with increased deaths for total cancer [HR=1.33, 95% confidence interval (CI) 1.04-1.70] and BCa [HR=2.1, 95% CI, 1.09-4.11]. The risk of total cancer [HR=1.7, 95% CI, 1.12-2.68], OLCas [HR=2.1, 95% CI, 1.00-4.37] and BCa [HR=3.8, 95% CI, 1.34-10.91] mortality was highest for women with all MetS components abnormal, compared to those without MetS. Linear associations of blood-pressure [HR=2.5, 1.02-6.12, Quartile (Q) 4 vs Q1, p trend=0.004] and blood-glucose [HR=2.2, 1.04-4.60, Q4 vs. Q1, p trend=0.04] with total-OLCas mortality were observed. A threefold increased risk of BCa mortality was observed for women with enlarged waist circumference, 100.9 cm, [HR=3.5, 1.14-10.51, p trend=0.008] and in those with increased blood glucose, 101 mg/dL, [HR=3.2, 1.11-9.20, p trend=0.03] compared to those in Q1. None of the components of MetS were associated with total-cancer mortality. CRP was not associated with cancer mortality. In conclusion, MetS is associated with total-cancer and breast-cancer mortality, with waist circumference, blood pressure and blood glucose as independent predictors of OLCas and BCa mortality. What's new? Metabolic syndrome (MetS) is closely associated with obesity and is a prognostic factor in obesity-linked cancers in women. MetS also is correlated with C-reactive protein (CRP), elevated levels of which are a risk factor for cancer. Whether MetS and CRP are jointly linked to cancer mortality, however, is unclear. In this study, MetS severity was associated with an increased risk of total cancer mortality and breast cancer mortality. Of MetS components, waist circumference, blood glucose and blood pressure were most strongly associated with mortality. CRP alone, however, was not significantly associated with total cancer, obesity-linked or breast cancer mortality.