The Association Between Vitamin D Status and Parameters for Bone Density and Quality is Modified by Body Mass Index

The association of vitamin D status with bone mineral density (BMD) and Quantitative Ultrasound measurements (QUS) has been inconsistent in previous studies, probably caused by moderating effects. This study explored (1) the association of vitamin D status with QUS and BMD, and (2) whether these associations were modified by body mass index (BMI), age, gender, or physical activity. Two-independent cohorts of the Longitudinal Aging Study Amsterdam (LASA-I, 1995/1996, aged ≥65; LASA-II, 2008/2009, aged 61–71) and baseline measurement of the B-vitamins for the prevention of osteoporotic fractures (B-PROOF) study (2008–2011, aged 65+) were used. QUS measurements [broadband ultrasound attenuation (BUA) and speed of sound (SOS)] were performed at the calcaneus in all three cohorts (N = 1,235, N = 365, N = 1319); BMD was measured by Dual X-ray absorptiometry (DXA) in B-PROOF (N = 1,162 and 1,192 for specific sites) and LASA-I (N = 492 and 503). The associations of vitamin D status with BUA and BMD were modified by BMI. Only in persons with low-to-normal BMI (<25 kg/m2) and serum 25(OH)D <25 nmol/L was associated with lower BUA as compared to the reference group (≥50 nmol/L) in LASA-I and B-PROOF. Furthermore, in LASA-I, these individuals had lower BMD at the hip and lumbar spine. In LASA-II, no associations with BUA were observed. Vitamin D status was not associated with SOS, and these associations were not modified by the effect modifiers tested. The association between vitamin D status and BUA and BMD was modified by BMI in the older-aged cohorts: there was only an association in individuals with BMI <25 kg/m2

Global vitamin D status and determinants of hypovitaminosis D

The aim of the study was to compare the structural and functional parameters of the myocardium in different genotypes of polymorphic markers BsmI (B/b) (rs1544410) and FokI (F/f) (rs2228570) of the vitamin D receptor gene (VDR) in individuals with cardiovascular diseases (CVD). Materials and Methods. We examined 198 patients with CVD. BsmI and FokI of the VDR gene were determined by the polymerase chain reaction. The blood levels of parathyroid hormone, 25(OH)D total, endothelin-1, plasma renin activity were revealed by the method of enzyme immunoassay. The calcium and phosphorus level in the blood was defined by the colorimetric method. Echocardiography was performed by GE Logic P5 Premium (Korea) with a phased sector sensor with a frequency of 2–4 MHz in the modes M-, B-, PW, CW. Results. All participants were divided into groups according to genotypes of FokI and BsmI of the VDR gene. For each polymorphism, the groups were comparable in age, CVD, blood pressure, heart rate, body mass index and levels of the estimated biomarkers. Significant differences (p &lt; 0.05) in the sizes of the aorta and the left atrium (LA), in the sizes and volumes of the left ventricle (LV) and its walls, the diameter of the LV outlet tract and the ejection fraction between the groups with the genotypes of FF and ff were established. In addition, differences (p &lt; 0.05) were found in the aorta size, LA and interventricular septum between the groups with the genotypes of ff and Ff. According to the genotypes of BsmI of the VDR gene, the groups did not differ significantly in the estimated structural and functional parameters of the myocardium and aorta. Hypertrophy of the LV is diagnosed in 78.6 % of participants. Conclusions. Polymorphism of FokI, but not of BsmI of the VDR gene is associated with structural and functional parameters of the myocardium and aorta in individuals with CVD in the Grodno region of Belarus. With the greatest frequency, LV hypertrophy occurs with Ff (37.9 %) and Bb (33.8 %).Цель исследования – сравнение структурно-функциональных показателей миокарда при разных генотипах полиморфных маркеров BsmI (B/b) (rs1544410) и FokI (F/f) (rs2228570) гена рецептора витамина D (VDR) у лиц с сердечно-сосудистыми заболеваниями (ССЗ). Материалы и методы. Обследовано 198 пациентов с ССЗ. Определение BsmI и FokI гена VDR проводили методом полимеразной цепной реакции. Содержание в крови паратиреоидного гормона, 25(OH)D общего, эндотелина-1, активность ренина плазмы определяли методом иммунофер- ментного анализа. Определение в крови уровня кальция и фосфора проводилось колориметрическим методом. Эхо- кардиография выполнялась аппаратом GE Logic P5 Premium (Корея) фазированным секторным датчиком с частотой 2–4 мГц в режимах М-, В-, PW, CW. Результаты. Все обследованные были разделены на группы по генотипам FokI и BsmI гена VDR. При каждом полиморфизме группы были сопоставимы по возрасту, ССЗ, значениям артериального давления, частоте сердечных сокращений, индексу массы тела и уровням оцененных биомаркеров. Установлены достоверные (p &lt; 0,05) отличия по размерам отделов аорты, левого предсердия (ЛП), размерам и объемам левого желудочка (ЛЖ) и его стенок, диаметром выходного тракта ЛЖ и фракцией выброса между группами с генотипом FF и ff. Кроме того, установлены отличия (p &lt; 0,05) по размерам отделов аорты, ЛП и толщиной межжелудочковой перегородки между группами с генотипом ff и Ff. По генотипам BsmI гена VDR группы достоверно не отличались по оцененным структурно-функциональным показателям миокарда и аорты. Гипертрофия ЛЖ диагностирована у 78,6 % обследованных. Заключение. Полиморфизм FokI, но не BsmI гена VDR ассоциирован со структурно-функциональными показателями миокарда и аорты у лиц с ССЗ у жителей Гродненского региона Беларуси. С наибольшей частотой гипертрофия ЛЖ встречается при Ff (37,9 %) и Bb (33,8 %) генотипах.