The aim of this study was to investigate seasonal variations in hip fracture incidence and mortality among older adults in Israel. Surprisingly, our findings indicate a higher incidence of hip fractures during the spring (30.8%) compared to other seasons, where the incidence was relatively consistent (22-24.2%). This unexpected pattern deviates from studies in various countries, including Israel [11, 12] which typically report increased hip fracture incidence during winter [4,5,6,7,8]. The inconsistency suggests a potential change in the activity levels of older adults in Israel, possibly influenced by the COVID-19 pandemic during 2021–2022. Older adults may have become more active following pandemic waves, consequently increasing their risk of falling and sustaining hip fractures. Notably, the higher incidence in spring, a comfortable season, does not rule out the role of weather conditions in hip fracture risk but does not strongly support it either.

In this study, individuals who fractured their hip in the spring were, on average, younger and had shorter hospital stays compared to those in other seasons. This implies that those experiencing hip fractures in spring were generally younger and in better health. These findings align with our hypothesis that the observed seasonal variation is linked to the activity levels of the elderly, with increased activity noted in the spring. These results resonate with a study by Solbakken et al., which found that the largest seasonal variations in hip fracture incidence occurred in the younger age group (50–64) and in the healthiest individuals, suggesting a correlation between physical activity and increased risk of falling [7].

Moreover, our study identified gender differences in hip fracture incidence, with a higher likelihood of hip fractures occurring in women during spring, and in men during autumn and winter. The lowest incidence among men was observed in spring (5.1%), while among women, there was a concentration of cases in spring (39.1%). These findings align with previous studies indicating gender-specific seasonal variations in hip fracture incidence [7, 17, 19]. Although the reasons for these gender differences remain unclear, our results suggest distinct patterns of activity between men and women across seasons, with women being more active in spring and men being less active during this season.

Furthermore, our study revealed significant variations in hip fracture incidence based on nationality and country of birth. Namely, Israelis had a higher likelihood of hip fractures in spring compared to non-Israelis (55.3% vs. 17.1%, respectively). Conversely, non-Israelis had a higher likelihood of hip fractures in winter compared to Israelis (30.0% vs. 14.7%, respectively). These disparities indicate a potential cultural influence on seasonal hip fracture patterns, possibly associated with various holidays observed in different communities.

Notably, no significant difference was observed in preoperative time to surgery among different seasons. As there is a mandated protocol in Israel to perform surgery within 24 h for patients with hip fractures, regardless of the season [20], this standardization likely accounts for the lack of variation in time to surgery observed across different seasons.

In terms of mortality, our study demonstrated a 20% mortality rate over the two-year follow-up period. While this proportion is lower than observed in a previous study in an Israeli cohort (30.0%) [21], it aligns with findings from an American cohort (23.5%) [22]. The differences may stem from methodological variations and distinct periods of data collection.

Moreover, our study revealed that patients who fractured their hip in autumn and winter had a lower life expectancy compared to those who sustained fractures in spring. This finding corroborates previous studies that reported higher mortality among patients presenting with hip fractures in winter months [5, 8, 23].

In our study, age accounted for approximately 8.6–13.5% of the variance in mortality rates, consistent with existing research showing that older age is associated with increased mortality following a hip fracture. This correlation underscores the physiological, social, and environmental factors contributing to higher mortality risk as individuals age. Physiological changes, prevalence of chronic illnesses, socioeconomic factors, and lifestyle choices all play significant roles in shaping mortality outcomes [24]. Importantly, seasonality emerged as an independent predictor of mortality after adjusting for gender, age, and nationality. This underscores the existence of seasonal variation in mortality following a hip fracture. The higher survival rate observed among patients who sustained a hip fracture in spring may be attributed to their overall better health status.