TY - JOUR T1 - Vitamin D and COPD: seasonal variation is important JF - Thorax JO - Thorax SP - 541 LP - 542 DO - 10.1136/thx.2009.134338 VL - 66 IS - 6 AU - Sundari N Ampikaipakan AU - David A Hughes AU - Jackie C Hughes AU - Talar Amen AU - Graham Bentham AU - Andrew M Wilson Y1 - 2011/06/01 UR - http://thorax.bmj.com/content/66/6/541.abstract N2 - Janssens et al1 have demonstrated the relationship between vitamin D status and lung function in patients with chronic obstructive pulmonary disease (COPD). However, in their study there was only one assessment of vitamin D status per patient. Given the minimal component of diet to vitamin D status (serum 25-hydroxyvitamin D (25(OH)D) concentration),2 it is mostly determined by sunlight exposure and has a seasonal variation in healthy individuals.3In a study of 24 patients with COPD (mean (SD) age 69 (5.8) years and smoking history 43 (15.8) pack-years) with measurements undertaken in the same individuals at the end of summer (August/September) and winter (March/April), we … ER -