Karadag MK, et al. - The purpose of this research was to investigate the association of vitamin D and parathyroid hormone (PTH) levels with nondipper hypertension and nocturnal decline in untreated hypertensive patients. In nondippers, significantly lower vitamin D levels and significantly higher PTH levels were evident. Data revealed that with nocturnal decline, vitamin D level was correlated positively and the PTH level was correlated negatively. Furthermore, findings indicated an independent association of PTH level with nocturnal decline in hypertension.