Israel Medical Association Journal

Background: Israel is a country with a sunny climate; however, vitamin D deficiency and insufficiency are common findings in certain populations whose exposure to sunlight is limited. Medical residency is known for long indoor working hours, thus theoretically limiting the opportunities for sun exposure.

Objectives: To evaluate whether the vitamin D status among residents in a single medical center in Tel Aviv is below the normal range.

Methods: Forty-six residents (28 females, 18 males, average age 33.9 ± 2.8 years) in three residency programs (internal medicine, general surgery/obstetrics and gynecology, pediatrics) were recruited. Demographic data, personal lifestyle, physical activity details and sun exposure duration were obtained by a questionnaire. Serum levels for 25(OH)D were analyzed by a radioimmunoassay.

Results: The mean serum 25(OH)D concentration was 29.8 ± 5.8 ng/ml. According to Institute of Medicine definitions, none of the residents were vitamin D deficient and only two residents (4%) were vitamin D insufficient (15 ng/ml each). The level of 25(OH)D was similar among the various medical specialties. The 25(OH)D levels correlated with the duration of sun exposure and the number of offspring (regression analysis: R2 = 9.2%, P < 0.04 and R2 = 8.9%, P < 0.04, respectively), but not with nutritional data, blood chemistry, or extent of physical activity. 

Conclusions: Most of the residents maintained normal or near normal 25(OH)D levels, indicating that the residency program itself did not pose a significant risk for vitamin D deficiency. 

 

Objectives: To assess the relationship between sleep deprivation, key metabolic markers, and professional performance in medical residents.

Methods: We compared 35 residents working the in-house night shift with 35 senior year medical students in a cross-sectional cohort study. The Epworth Sleepiness Scale (ESS) questionnaire was administered and blood tests for complete blood count (CBC), blood chemistry panel, lipid profile and C-reactive protein (CRP) were obtained from all participants.

Results: Medical students and medical residents were comparable demographically except for age, weekly working hours, reported weight gain, and physical activity. The ESS questionnaires indicated a significantly higher and abnormal mean score and higher risk of falling asleep during five of eight daily activities among medical residents as compared with medical students. Medical residents had lower high density lipoprotein levels, a trend towards higher triglyceride levels and higher monocyte count than did medical students. CRP levels and other laboratory tests were normal and similar in both groups. Among the medical residents, 5 (15%) were involved in a car accident during residency, and 63% and 49% reported low professional performance and judgment levels after the night shift, respectively.

Conclusions: Medical residency service was associated with increased sleepiness, deleterious lifestyle changes, poorer lipid profile, mild CBC changes, and reduced professional performance and judgment after working the night shift. However, no significant changes were observed in CRP or in blood chemistry panel. Larger prospective cohort studies are warranted to evaluate the dynamics in sleepiness and metabolic factors over time.