Urgent need of vitamin D supplementation among Iranian elderly: a cross-sectional study

Dear Editor: Fortification programs are not established for nutrients like vitamin D among other nutrients in Iran. It is reported that approximately 80% of Iranians do not meet the estimated average requirement for calcium and vitamin D [1] . The Iranian Multicenter Osteoporosis Study (IMOS) has shown that more than 80% of Iranians have vitamin D deficiency [2] . However, currently, there is no data on vitamin D supplementation in elderly adults in Iran. We carried out a secondary analysis of a bigger population-based cross-sectional study, which was conducted among elderly men and women in the 6 th district of Tehran to determine the frequency of sarcopenia [3] . Using cluster random sampling, we chose 30 clusters in the 6 th district of the Tehran Municipality in collaboration with the Iran Post Office. The head of the clusters was selected based on a ten-digit postal code and subjects were asked for home interviews. Sampling was performed in each cluster in clockwise order until the desired sample size was reached. In each cluster, two individuals (one male and one female) were invited from each of the following age groups: 55-59, 60-64, 65-69, 70-74, and over 75 years with 10 persons in each cluster. During the home interviews, they were briefed about the project and its objectives. For those who agreed to participate, clinic appointments were set. Participants were asked to comply with the following requirements prior to their appointments: a) no pregnancy, b) fasting for 10 hours prior to testing, c) not using any calcium supplements two days prior to testing, and d) not using any metal objects. Inclusion criteria were: a) age at least 55 years, b) the ability to move without crutches, walker or other assistive devices, c) no artificial limbs or limb prosthesis, d) no active cancer by self report, e) no congestive heart failure, chronic obstructive pulmonary disorder, chronic renal failure, liver cirrhosis and liver failure. Information on demographic, medical history, anthropometric, vitamin D supplementation and bone mineral density (BMD) was recorded. Participants were categorized as users or non-users of vitamin D supplements based on information from both the medication and supplement sections of the questionnaire. Dosages and duration of calcium-vitamin D supplement were not recorded. Three questionnaires including a general questionnaire, a physical activity questionnaire [4] , and a food frequency questionnaire (FFQ) [5]