Department of Biochemistry, Faculty of Medicine

To examine whether the prevalence and severity of hyperostosis frontalis interna (HFI) has significantly changed during the past 100 years. Two female populations, 100 years apart, were studied; 992 historic and 568 present day females. Detection of HFI was carried out via direct observation or CT images (Brilliance 64, Philips Medical Systems, Cleveland, Ohio). HFI was graded according to Hershkovitz et al.’s (1999) 4-scale definition and according May et al.’s (2010c) 3-scale definition. Following correction for age, present day females manifested a significantly higher HFI prevalence compared with historic females (P < 0.05). The risk of developing HFI was found to be approximately 2.5 times greater in present day females compared with females living 100 years ago (P < 0.05). In the young age cohort, present day females manifested a significantly higher prevalence of HFI type B (P < 0.05), whereas in the old age cohort, a significant difference in the prevalence of HFI types C and D was noted between the two groups (P < 0.05). HFI tended to appear at a younger age in the present population. The last two decades has witnessed an increase in HFI prevalence(from 55.6% to 75%). HFI prevalence has increased during the last century, especially among young individuals, possibly indicating a profound change in human fertility patterns, together with the introduction of various hormonal treatments) and new dietary habits.