Urban tropospheric ozone increases the prevalence of vitamin D deficiency among Belgian postmenopausal women with outdoor activities during summer.
BACKGROUND
By absorbing sunlight UVB and thereby reducing cutaneous vitamin D photosynthesis, ozone, a common urban pollutant, could cause hypovitaminosis D.


OBJECTIVE
The objective of the study was to establish the characteristics and percentage of subjects with serum 25-hydroxyvitamin D [25(OH)D] less than 75 nmol/liter among postmenopausal women engaging in outdoor activities in either Brussels or the countryside.


METHODS
This was a cross-sectional study conducted in a university research hospital.


METHODS
Among 249 women consulting for either shoulder tendonitis or lumbar spine osteoarthritis, 121 free of conditions and drugs affecting bone and calcium metabolism completed two food-frequency questionnaires within 15 d and we selected the 85 subjects with retest scores within the +/- 15% of test scores. Other parameters included sun exposure index (SEI), PTH levels, and femoral neck T-score.


RESULTS
Urban residents (n = 38) and rural residents (n = 47) did not differ in mean ages, body mass indices, and vitamin D intakes. When compared with rural inhabitants, urban inhabitants were exposed to ozone levels 3 times higher, and despite a higher mean SEI (113 vs. 87; P < 0.001), they had a higher prevalence of 25(OH)D less than 75 nmol/liter (84 vs. 38%). After adjusting for SEI, 25(OH)D was 2-fold higher in rural residents, and after adjusting for 25(OH)D, SEI was 3-fold higher in urban residents. Femoral neck T-scores correlated positively with 25(OH)D and negatively with PTH levels.


CONCLUSIONS
Air pollution may be a neglected risk factor for hypovitaminosis D, which is known to compromise several health outcomes. As long as 25(OH)D is greater than 75 nmol/liter, calcium intakes greater than 17.5 mmol/d are unnecessary to prevent elevations in PTH levels.
Manicourt
Daniel-Henri
DH
Department of Rheumatology, St. Luc University Hospital, UCL 5390, 1200 Brussels, Belgium. manicourt@bchm.ucl.ac.be
Devogelaer
Jean-Pierre
JP
D000368:Aged; D000369:Aged, 80 and over; D001272:Atmosphere; D001530:Belgium / Q000453:epidemiology; D015519:Bone Density / Q000187:drug effects / Q000502:physiology; D002947:Cities; D005260:Female; D005272:Femur Neck / Q000000981:diagnostic imaging; D006801:Humans; D008875:Middle Aged; D009043:Motor Activity / Q000187:drug effects / Q000502:physiology*; D010126:Ozone / Q000494:pharmacology*; D010281:Parathyroid Hormone / Q000097:blood; D017698:Postmenopause / Q000187:drug effects; D015995:Prevalence; D011859:Radiography; D012621:Seasons; D013472:Sunlight; D014807:Vitamin D / Q000031:analogs & derivatives / Q000097:blood; D014808:Vitamin D Deficiency / Q000097:blood / Q000453:epidemiology*
D010281:Parathyroid Hormone; D014807:Vitamin D; D010126:Ozone; C104450:25-hydroxyvitamin D