Association of NAD levels with metabolic disease in a community-based study.

Background: Nicotinamide adenine dinucleotide (NAD) is a coenzyme and plays a crucial role in several metabolic processes. This study explored the association of nicotinamide adenine dinucleotide (NAD) levels with metabolic disease (MD) in adults.

Methods: In this cross-sectional study, all data were collected from the Jidong community. MD was defined as the presence of one or more of the following disease components: hypertension, dyslipidemia, diabetes, hyperuricemia, obesity, and non-alcoholic fatty liver disease (NAFLD). The MD components were categorized into three groups: those with one component, those with two components, and those with three to six components. The whole blood NAD level was measured using a cycling assay and LC-MS/MS analysis. The participants were divided into four groups based on their NAD level quartiles. Multivariable logistic regression was used to evaluate the association of the whole blood NAD levels with MD.

Results: Of the 1,394 eligible participants, the average age was 43.2 years, and 74.3% had MD. In the top quartile of NAD, the prevalence of MD and each of its components (hypertension, hyperlipidemia, diabetes, hyperuricemia, obesity, and NAFLD) were 87.9% 35.2%, 62.3%, 8.7%, 36.9%, 21.0%, and 60.5%, respectively. As compared with the lowest NAD quartile (≤29.4 μmol/L), the adjusted odds ratios and 95% confidence interval of the highest quartile were 3.01 (1.87-4.87) for MD, 2.48 (1.44-4.29) for 1 MD component, 2.74 (1.45-5.17) for 2 MD components, and 4.30 (2.32-7.98) for 3-6 MD components. The risk of MD began to increase at NAD levels of 31.0 μmol/L, as revealed by the gradient associations of NAD levels with MD. There was no significant interaction between age, sex, drinking, smoking, and NAD for MD (p for interaction ≥0.10).

Conclusions: Increased NAD was significantly associated with MD, as well as its individual components. Our findings provide new evidence for the relationship between blood NAD levels and MD.