Nightmares and bad dreams among individuals with musculoskeletal pain: a link to vitamin D and calcium.

Nightmares are frightening or disturbing dreams that awaken sleepers while bad dreams are disturbing dreams that do not awaken sleepers. Both types are known to be associated with psychological symptoms including anxiety and depression. Chronic pain is often comorbid with psychological symptoms and vitamin D deficiency increases risk of chronic musculoskeletal pain (MSP), which in turn is associated with increased risk of anxiety and depression. We aimed to investigate associations between types of dreams, psychological symptoms, vitamin D, and calcium intake in individuals with MSP. The study included 191 outpatients with MSP and 191 age/gender matched healthy controls. Psychological symptoms were assessed using Hospital Anxiety and Depression Scale. Serum vitamin D was measured and daily calcium intake was estimated. Participants were asked about types of their dreams (normal, bad, or nightmares) during the past month. Binary logistic regression was used to find predictors of MSP and bad dreams and nightmares. Bad dreams and nightmares, vitamin D deficiency, low calcium intake, anxiety, and depression were more prevalent in cases controls (Ps<0.001). Chi-square analyses showed that types of dreams were associated with anxiety, depression, and MSP (Ps<0.001). Participants with normal dreams had higher vitamin D (P<0.01) and calcium intake (P<0.001) and lower anxiety and depression scores (Ps<0.001) compared to participants with bad dreams and nightmares. Anxiety, depression and MSP were predictors for bad dreams and nightmares. Further studies are required to assess if vitamin D supplementation and increasing calcium intake may improve MSP, psychological symptoms and thus prevent nightmares and bad dreams.