Association of cumulative monocyte to high-density lipoprotein ratio with the risk of type 2 diabetes: a prospective cohort study.

BACKGROUND: Recent studies have established that monocyte-derived inflammation plays a central role in the pathogenesis of type 2 diabetes mellitus (T2DM). It is unclear whether chronic metabolic inflammation, reflected by the cumulative monocyte to high-density lipoprotein ratio (CumMHR), predisposes the general population to T2DM. METHODS: This study included 40,813 participants without diabetes from a real-life, community-based cohort (the Kailuan Study) attending a 2-year cycle of health survey since 2006. Cumulative exposure was obtained from 2006/2007 to 2010/2011. Follow-up started at 2010/2011 and through 2020. Multivariable-adjusted Cox regression models were used to calculate the CumMHR-associated risk of incident T2DM. RESULTS: Over a median follow-up period of 7.98 (IQR: 5.74-8.87) years, 4,848 T2DM cases occurred. The CumMHR was positively associated with the risk of incident T2DM after adjusting for age, sex, smoking, drinking habits, physical activities, BMI, triglyceride-glycemia index, log(leukocyte count), log(hsCRP), blood pressure, renal function, and medication uses with adjusted HRs of 1.0 (ref.), 1.18 (1.05‒1.25), 1.17 (1.07‒1.27), 1.38 (1.26‒1.50), respectively, in CumMHR Quartiles 1, 2, 3 and 4. When follow-up ended at 2014/2015, the short-term (4‒year) adjusted T2DM risks in CumMHR Quartiles 2, 3, and 4 were 1.14 (1.01‒1.29), 1.17 (1.04‒1.32), 1.40 (1.25‒1.58), respectively, relative to Quartile 1. A significant interaction between CumMHR and cumulative high-sensitivity C-reactive protein (CumCRP) was observed (P-interaction: 0.0109). The diabetic risk in the highest quartile of CumMHR was higher (1.53 [1.28‒1.84]) when CumCRP < 1 mg/L, attenuated with increasing CumCRP levels (1 ~ 10 mg/L) and disappeared in CumCRP ≥ 10 mg/L. Hypertension, overweight, or smoking habits further modified the CumMHR-associated diabetic risk. CONCLUSIONS: Cumulative MHR may be a promising supplement to hsCRP for more comprehensively assessing the influence of metabolic inflammation on T2DM susceptibility. For primary prevention, targeting high CumMHR, especially in cases at low risk of diabetes defined by traditional risk factors, may further help reduce the diabetic risk.