title: [Relation between the incidence of fractures of the upper part of the femur and the season of the year].
abstract: A number of patients hospitalized at the Osijek General Hospital Surgical Ward with hip fractures determined for a ten-year period (1976-1985) indicates that the number of these injuries during a period of year with less sunny hours (November to February, i.e. during winter) exceeds by 66.6% (p less than 0.0005) the number of injuries during summer, i.e. the period of year with larger number of sunny hours (May to September). There are mathematical proofs that occurrence of these injuries is partially periodical and that there is a statistically significant negative correlation between the number of sunny hours (quantity of ultraviolet rays) and the number of hip fractures (r = 0.487, p less than 0.0005). Based on numerous data available in literature on presently known physiological functions and oscillations of vitamin D, some basic postulates on hip biomechanics, earlier analyses done by the authors regarding frequency of this type of injury depending on age, sex, laterality and fracture site, and supported by the results presented in this paper, it has been concluded that reduced frequency of hip fractures in affected population during periods with more of ultraviolet radiation could be partially explained by a more potent muscle contraction, smaller instability and consequently reduced frequency of falls during this period of year.
authors.forename: B
authors.initials: B
authors.lastname: Has
authors.forename: E
authors.initials: E
authors.lastname: Has-Schön
mesh_terms: D006620:Hip Fractures / Q000453:epidemiology*; D006801:Humans; D012621:Seasons; D015022:Yugoslavia
vernacular_title: Ovisnost ucestalosti prijeloma gornjeg okrajka natkoljenicne kosti o godisnjem dobu.