Age-Related Changes in the 25-Hydroxyvitamin D Versus Parathyroid Hormone Relationship Suggest a Different Reason Why Older Adults Require More Vitamin D

Vieth, Reinhold; Ladak, Yasmin; Walfish, Paul G.

doi:10.1210/jc.2002-021064

Cited by 382 publications

(295 citation statements)

References 29 publications

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“…This secondary hyperparathyroidism is parallel to observations in several non-postpartum populations (DawsonHughes et al, 1991;Brot et al, 2001;Lips, 2001;Jesudason et al, 2002;Vieth et al, 2003;Mosekilde, 2005). The increased plasma levels of PTH affect calcium homeostasis probably by increasing renal calcium reabsorption and enhancing renal 1.25(OH) 2 D synthesis.…”

Section: Discussionsupporting

confidence: 72%

Postpartum vitamin D insufficiency and secondary hyperparathyroidism in healthy Danish women

et al. 2006

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Objective: To examine vitamin D status and parathyroid function in normal Danish women postpartum. Design: Three cross-sectional measures during follow-up of 89 women postpartum. Subjects and intervention:We assessed vitamin D status by measuring plasma 25-hydroxyvitamin D (P-25OHD) and the degree of secondary hyperparathyroidism by measuring plasma parathyroid hormone (P-PTH) in 89 Caucasian women at three consecutive visits: (mean (range)) 23 (10-37) days (spring), 117 (95-140) days (late summer) and 274 (254-323) days (winter) postpartum. Results: P-25OHD showed seasonal variations with higher values in late summer than in the other periods (Po0.001). At the first visit, 65% received vitamin D supplements. At the following visits, almost 50% were supplemented. Vitamin D insufficiency (P-25OHDo50 nmol/l) occurred more often during winter (28%) than in spring (14%) (Fisher's exact test, P ¼ 0.02) or late summer (7%) (P ¼ 0.0001). Irrespective of season, vitamin D insufficiency occurred most frequent in women who did not take vitamin D supplements (Fisher's exact test, Po0.02). Frank vitamin D deficiency (P-25OHDo25 nmol/l) was observed during winter in 6%. At all three periods, P-25OHD correlated inversely with P-PTH indicating secondary hyperparathyroidism at deficient vitamin D status. During spring, late summer and winter three, one and four females, respectively, had elevated plasma PTH. Conclusion: Vitamin D insufficiency with secondary hyperparathyroidism is a frequent finding in healthy Danish women postpartum and especially during winter. Vitamin D supplements reduced the risk of vitamin D insufficiency, especially during winter. Our results support the importance of increased alertness regarding information of pregnant and lactating women about vitamin D supplements. Furthermore, it has to be studied whether the present recommendations of an intake of 5-10 mg vitamin D/day are sufficient, especially during winter months.

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Section: Discussionsupporting

confidence: 72%

Postpartum vitamin D insufficiency and secondary hyperparathyroidism in healthy Danish women

et al. 2006

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“…The fact that the patients with diabetes mellitus frequently have diabetic neuropathy which increases the risk of fall suggests that hypovitaminosis D is a more serious problem for diabetic patients than normal subjects. It has been reported that rather more vitamin D store is necessary in elderly people to overcome the hyperparathyroidism associated with their diminished renal function, and that serum concentration of 25-OHD increases according to age in the normal population [22,23]. In this study, we found that there was a positive association between age and serum concentration of 25-OHD also in the type 2 diabetes population, though not statistically significant.…”

Section: Discussioncontrasting

confidence: 41%

Hypovitaminosis D in Type 2 Diabetes Mellitus: Association with Microvascular Complications and Type of Treatment

et al. 2006

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Abstract. The prevalence of hypovitaminosis D has been recently reevaluated, and diabetes is considered as a risk factor for osteoporosis. We studied the association of the prevalence of hypovitaminosis D with the clinical features of diabetes. We conducted the observational study in 581 Japanese patients with type 2 diabetes mellitus and 51 normal subjects, and analyzed the relationship between serum 25-hydroxyvitamin D (25-OHD) concentration and the clinical features associated with type 2 diabetes. Mean serum 25-OHD concentration in type 2 diabetes patients was 17.0 ± 7.1 ng/ml (Mean ± SD) in winter, and was not statistically different from normal population (17.5 ± 3.6 ng/ml). The prevalence of hypovitaminosis D (<20 ng/ml) was 70.6%. Serum concentrations of 25-OHD were associated with HbA1c (P = 0.013), age (P = 0.070) and serum albumin (P<0.001), but were not related to BMI or the duration of diabetes. The levels of 25-OHD were significantly lower in the population with apparent microvascular complications, although serum creatinine levels were below 2.0 mg/dl. Serum 25-OHD concentrations in the group treated with insulin (15.4 ± 6.5 ng/ml) was lower than those in the patients treated with diet alone (20.8 ± 7.6 ng/ml) and with oral hypoglycemic agents (17.3 ± 7.0 ng/ml). Furthermore, the highest incidence of osteoporotic fracture and/or back deformity was observed in insulin-treated patients with hypovitaminosis D. In conclusion, these results suggest that microvascular complications and insulin treatment in type 2 diabetes patients are associated with the co-existence of hypovitaminosis D, and that hypovitaminosis D in insulin-treated patients is possibly related to the risk of osteoporotic fracture.

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“…Este declínio pode ser causado por deficiência dietética e diminuição endógena na produção de vitamina D. Esta diminuição da produção é devida, em parte, à menor exposição solar nos grupos etários mais avançados. Além disso, com o processo de envelhecimento, ocorrem piora da função renal e diminuição da produção de vitamina D, com conseqüente hiperparatireoidismo secundário (17). Nas mulheres, a diminuição estrogênica observada após a menopausa também reduzirá a produção renal de 1,25(OH) 2 D. Por outro lado, o alto turnover ósseo que ocorre nos primeiros anos da menopausa pode inibir a absorção intestinal de Ca devido à mobilização do osso mineral, com diminuição da secreção do PTH e da 1-hidroxilação da 25-OHD (7).…”

Section: Menopausa/envelhecimentounclassified

Biodisponibilidade do cálcio dietético

Buzinaro

Almeida

Mazeto

2006

Arq Bras Endocrinol Metab

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RESUMOO cálcio (Ca) dietético é fundamental para a saúde óssea. Tanto o teor como a biodisponibilidade do elemento nos alimentos devem ser considerados. Este artigo objetiva sumarizar os fatores envolvidos na absorção e destacar os alimentos com melhor disponibilidade do Ca. Este é absorvido principalmente no jejuno e o pH baixo parece favorecer sua absorção, que é maior no crescimento, na gestação/lactação e na carência de Ca ou fósforo (P), e menor no envelhecimento. As maiores fontes, e com melhor absorção, são os laticínios bovinos. Outros alimentos apresentam concentrações elevadas de Ca, mas com biodisponibilidade variável: os ricos em ácidos oxálico e fítico apresentariam uma menor absorção, enquanto que os ricos em carboidratos teriam uma absorção maior. Por apresentarem uma biodisponibilidade do Ca mais próxima da do leite bovino, o leite de outros animais, o de soja enriquecido e alguns vegetais, em quantidades adequadas, poderiam ser usados como alternativas a este. Dietary calcium (Ca) is fundamental to the bone's health. Both the purport and the element bioavailability in the food need to be considered. The purpose of this work was to summarize the factors involved in Ca absorption and point out the sources with higher bioavailability. Ca is mostly absorbed in the jejunum and low pH seems to favor its absorption, which is higher during growth, gestation/lactation and Ca and phosphorus (P) deficiency, and lower with aging. The richest and bestabsorbed Ca source is cow's milk and its derivatives. Other foods show high Ca concentrations but variable bioavailability: foods rich in phytates and oxalates show a smaller absorption and carbohydrate-rich foods show higher absorption. Since Ca bioavailability in other animal's milk, soymilk and some vegetables is closer to that in cow's milk, adequate amounts of these foods could be used as an alternative. O CRESCIMENTO E A MANUTENÇÃO do tecido ósseo dependem de uma grande variedade de fatores genéticos e ambientais. A hereditariedade contribui com cerca de 60 a 70% da expressão fenotípica da densidade mineral óssea (DMO), um dos mais importantes marcadores da saúde do osso. Por outro lado, fatores ambientais tais como dieta e estilo de vida revisãoBiodisponibilidade do Cálcio Dietético

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Age-Related Changes in the 25-Hydroxyvitamin D Versus Parathyroid Hormone Relationship Suggest a Different Reason Why Older Adults Require More Vitamin D

Cited by 382 publications

References 29 publications

Postpartum vitamin D insufficiency and secondary hyperparathyroidism in healthy Danish women

Postpartum vitamin D insufficiency and secondary hyperparathyroidism in healthy Danish women

Hypovitaminosis D in Type 2 Diabetes Mellitus: Association with Microvascular Complications and Type of Treatment

Biodisponibilidade do cálcio dietético

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