Applied nutritional investigation Seemingly paradoxical seasonal influences on vitamin D status in nursing-home elderly people from a Mediterranean area Francisca Pérez-Llamas, Ph.D. a,, *, María José López-Contreras, Ph.D. a , María José Blanco, Ph.D. b , Fernando López-Azorín, Ph.D. c , Salvador Zamora, Ph.D. a , and Olga Moreiras, Ph.D. d a Department of Physiology, University of Murcia, Murcia, Spain b Social Action Institute of Murcia, Murcia, Spain c Clinical Analysis Service, University Hospital “Virgen de la Arrixaca”, Murcia, Spain d Department of Nutrition, University Complutense of Madrid, Madrid, Spain Manuscript received August 1, 2007; accepted January 4, 2008. Abstract Objective: We investigated vitamin D status in institutionalized elderly subjects by measuring serum 25-hydroxyvitamin D (25[OH]D) and its association with season and other factors: age, gender, nutritional status, cognitive function, functional ability, dietary intake, vitamin D supple- ment consumption, and disease. Methods: The cross-sectional study included 86 subjects, 65–94 y of age (29 men and 57 women), who lived in three nursing homes in Murcia, a Spanish Mediterranean area. The Mini Nutritional Assessment, Short Portable Mental Status Questionnaire, and BI were used to evaluate nutritional status, functional ability, and cognitive function, respectively. Serum 25(OH)D concentrations were used to assess vitamin D status. The thresholds of inadequacy were considered to be 25 nmol/L (vitamin D deficiency) and 50 nmol/L (vitamin D insufficiency). Results: Body mass index was 28.8  5.8 kg/m 2 (mean  SD). Vitamin D dietary intake was very much below the recommended dietary intake. The Mini Nutritional Assessment was 23.6  4.0, cognitive function was 7.8  1.9, and functional ability 82.9  23.1. The percentages of subjects with inadequate serum 25(OH)D concentrations were 58.2% and 32.6%, taking into consideration cutoffs of 50 and 25 nmol/L, respectively. Vitamin D deficiency was more common in women (40.3%) than in men (20.7%). Serum 25(OH)D concentrations varied significantly with the season in which the samples were taken, but not with the other factors analyzed. Conclusion: In this Mediterranean area, a substantial percentage of institutionalized subjects showed an inadequate vitamin D status, which could be remedied by the consumption of vitamin D–fortified foods and/or vitamin D supplements, especially during the summer months. © 2008 Elsevier Inc. All rights reserved. Keywords: Vitamin D; 25-Hydroxyvitamin D deficiency; Dietary intake; Nutrition; Mini Nutritional Assessment; Elderly; Nursing home; Institutionalization Introduction Vitamin D deficiency has been found to be prevalent among elderly populations in many regions of the world [1– 6]. In community-dwelling elderly people, the preva- lence of vitamin D deficiency is 5–25% and this is much greater (48 – 80%) in the institutionalized elderly population [7–10]. Vitamin D is produced endogenously when the skin is exposed to sunlight (ultraviolet B 290 –315 nm) and can be obtained exogenously from a few natural food sources and by food fortification and supplements. Several factors po- tentially affect vitamin D status. These include genetic fac- tors, adiposity, and factors affecting the cutaneous synthesis of vitamin D such as skin pigmentation, age, season, lati- This study was supported by the Social Action Institute of Murcia, Murcia Region Government, Spain. * Corresponding author. Tel.: +968-364-942; fax: +968-363-963. E-mail address: frapella@um.es (F. Pérez-Llamas). Nutrition 24 (2008) 414 – 420 www.elsevier.com/locate/nut 0899-9007/08/$ – see front matter © 2008 Elsevier Inc. All rights reserved. doi:10.1016/j.nut.2008.01.006