Seasonal variation, hip fracture and vitamin D levels in Southern Tasmania

To determine the frequency of vitamin D deficiency in older patients admitted with a hip fracture and to look for seasonal variation in vitamin D levels and hip fracture in Southern Tasmania.

This was a case series of patients admitted to the Royal Hobart Hospital, Tasmania with a hip fracture from July 1996-June 1997. Information was collected on demographic data, functional activity, associated medical disorders and drug history.

There were 91 patients, 66 female with a mean age of 81.3 years. Vitamin D deficiency, defined as a serum 1,25 hydroxyvitamin D level <28 nmol/L was present in 67% of subjects. Vitamin D levels were low throughout the year without significant seasonal variation. There was no seasonal variation in admissions with a hip fracture. The majority of patients (68%) either lived in institutional care or were dependent on a carer and 43% reported going outdoors less than once a week.

The high incidence of vitamin D deficiency in these subjects admitted with a hip fracture reflects reduced sunlight exposure and poor diet and is probably a marker of frailty. The absence of seasonal variation reflects a frailer population likely to be housebound, less mobile and more likely to have falls and sustain a fracture. Older and frailer people may benefit from routine screening for vitamin D deficiency, and replacement therapy should be considered for those found to be deficient.