The evidence on the relationship of pyridoxal 5′-phosphate (PLP) with sleep-related problems is limited and controversial. Notably, there is a lack of studies on the general population and studies of the dose–response relationship. Therefore, we conducted a cross-sectional study to examine the associations between serum PLP concentration and sleep-related problems (sleep quality and sleep duration) in adults, using the data of the National Health and Nutrition Examination Survey 2005–2010. High-performance liquid chromatography (HPLC) was used to test PLP in blood samples. Sleep quality and sleep duration were based on self-reported data, with sleep quality categorized as sleep disorder, trouble falling asleep, waking up during the night, and daytime sleepiness. The primary analyses utilized logistic regression models and restricted cubic spline. Compared with the first quartile (Q1), the odds ratios (ORs) and 95% confidence intervals (CIs) of daytime sleepiness for the Q2 and Q3 of serum PLP concentrations were 0.76 (0.59–0.99) and 0.78 (0.62–0.98), respectively. The relationship was only significant for males. Furthermore, a non-linear dose–response relationship was observed between serum PLP concentration and the risk of daytime sleepiness. Compared with the normal sleep duration group, serum PLP concentrations were negatively associated with the risks of very short, short, and long sleep duration, with relative risk ratios (RRRs) of 0.58 (0.43–0.81) (Q4), 0.71 (0.61–0.83) (Q4) and 0.62 (0.34–0.94) (Q3), respectively. The average serum PLP concentrations were higher in people with normal sleep duration, suggesting a non-linear dose–response relationship. Our study indicated that serum PLP concentrations were negatively associated with daytime sleepiness, and this association may only exist in males. Moreover, it was also inversely related to abnormal sleep duration (very short, short, long) compared to normal sleep duration.

Background: The aim of the current study was to explore the trajectories, variabilities, and cumulative exposures of body mass index (BMI) and waist circumference (WC) with cardiac arrhythmia (CA) risks. Methods: In total, 35,739 adults from the Kailuan study were included. BMI and WC were measured repeatedly during the 2006–2010 waves. CA was identified via electrocardiogram diagnosis. BMI and WC trajectories were fitted using a group-based trajectory model. The associations were estimated using Cox proportional hazards models. Results: We identified four stable trajectories for BMI and WC, respectively. Neither the BMI trajectories nor the baseline BMI values were associated with the risk of CA. Compared to the low-stable WC group, participants in the high-stable WC group had a higher risk of CA (hazard ratio (HR) = 1.40, 95% confidence interval (CI): 1.06, 1.86). Interestingly, the cumulative exposures of BMI and WC instead of their variabilities were associated with the risk of CA. In the stratified analyses, the positive associations of the high-stable WC group with the risk of CA were found in females only (HR = 1.98, 95% CI: 1.02, 3.83). Conclusions: A high-stable WC trajectory is associated with a higher risk of CA among Chinese female adults, underscoring the potential of WC rather than BMI to identify adults who are at risk.