Vitamin D supplementation for cystic fibrosis

 

Abstract

Background

Cystic fibrosis (CF) is a genetic disorder with multiorgan effects. In a subgroup with pancreatic insufficiency malabsorption of the fat soluble vitamins (A, D, E, K) may occur. Vitamin D is involved in calcium homeostasis and bone mineralisation and may have extraskeletal effects. This review examines the evidence for vitamin D supplementation in CF.

Objectives

To assess the effects of vitamin D supplementation on the frequency of vitamin D deficiency, respiratory outcomes and vitamin D toxicity in the CF population.

Search methods

We searched the Cochrane CF and Genetic Disorders Group Trials Register comprising references identified from comprehensive electronic database searches and handsearches of relevant journals and abstract books of conference proceedings.

Most recent search: 14 March 2011.

Selection criteria

Randomised and quasi-randomised controlled trials of vitamin D supplementation compared to placebo in the CF population regardless of exocrine pancreatic function.

Data collection and analysis

Both authors independently assessed the 'risk of bias' of each included trial and extracted outcome data (from published trial information) for assessment of bone mineralization, growth and nutritional status, frequency of vitamin D deficiency, respiratory status, quality of life and adverse events.

Main results

Three studies are included, although only data from two were available (41 adults and children with CF). One of these studies compared supplemental 800 international units (IU) vitamin D and placebo for 12 months in 30 osteopenic pancreatic insufficient adults; both groups continued 900 IU vitamin D daily. The other (abstract only) compared supplemental 1g calcium alone, 1600 IU vitamin D alone, 1600 IU vitamin D and 1g calcium and placebo in a double-blind randomised cross-over trial; only 11 children (vitamin D and placebo groups) after six-months supplementation are included; inclusion criteria, pancreatic sufficiency or disease status of participants are not defined. There were no significant differences in primary or secondary outcomes in either study. The studies are not directly comparable due to differences in supplementation, outcome reporting and possibly participant characteristics (eg severity of lung disease, growth and nutrition, pancreatic sufficiency). There were no adverse events in either study. The third study (abstract only) compared daily calcitriol (0.25 or 0.5 micrograms) with placebo in pancreatic insufficient children and young adults, only pre-intervention data were available.

Authors' conclusions

There is no evidence of benefit or harm in the limited number of small-sized published trials. Adherence to relevant CF guidelines on vitamin D should be considered until further evidence is available.

 

Plain language summary

The use of regular vitamin D preparations for children and adults with cystic fibrosis

Cystic fibrosis with pancreatic insufficiency can cause vitamins, such as vitamin D, to be inadequately absorbed leading to vitamin deficiencies. Lack of vitamin D (vitamin D deficiency) can cause specific problems such as bone deformity and bone fractures. It can also be associated with poorer general and respiratory health. Thus, people with cystic fibrosis are usually given regular vitamin D preparations from a very young age. However, excess vitamin D can also cause respiratory problems and problems with high calcium levels. The review contains three trials, but we could only extract data from two trials. We found no evidence to show whether giving vitamin D regularly to people with cystic fibrosis is beneficial or not. The authors are unable to draw any conclusions regarding the routine administration of Vitamin D supplements and recommend that until further evidence is available, local guidelines are followed regarding this practice.

 

摘要

背景

在囊狀纖維化患者補充維生素D

囊狀纖維化(CF)是一種遺傳性疾病，會造成多重器官的影響。其中有胰臟功能不全者可能會有脂溶性維生素(A、D、E、K)吸收不良的情形。維生素D的功能在維持血液中鈣離子的平衡及骨質密度，也可能有骨骼外的影響。本回顧在檢驗囊狀纖維化患者補充維生素D的證據。

目標

評估囊狀纖維化患者補充維生素D之成效，包括維生素D不足之發生率、呼吸狀況及維生素D的毒性。

搜尋策略

我們搜尋Cochrane囊狀纖維化和遺傳性疾病的試驗登錄，其包括全面性的電子資料庫檢索，人工檢索相關期刊、會議手冊。 最後更新日期：2009年6月9日。

選擇標準

在囊狀纖維化患者，不考慮胰液分泌功能，以隨機及類隨機的對照試驗比較使用維生素D補充的與使用安慰劑的差別。

資料收集與分析

有兩位作者分別做了�風險偏差�評估，包含了試驗及所提出來的成果(從發表的試驗訊息)，評估了骨質密度、生長情形和營養狀態、維生素D缺乏的發生率、呼吸狀態、生活品質及不良反應。

主要結論

有三個研究被納入，但只取得兩個研究的研究數據(包括了41位囊狀纖維化的成人和小孩)。第一個研究是以30位骨質減少且胰臟功能不全的患者，在補充800國際單位(IU)的維生素D和安慰劑12個月後的比較，兩組持續每天給予維生素D900國際單位。另一個研究(只有摘要)以雙盲交叉試驗比較分別補充1公克的鈣、1600國際單位的維生素D、1600國際單位的維生素D加上1公克的鈣和安慰劑之差異；只有11個孩子(維生素D組及安慰劑組)在補充6個月後的結果被納入本回顧，至於患者被納入的條件，胰臟功能不全的狀態或受試者疾病狀態未被說明。在這兩個試驗中，不論主要成果或次要成果並沒有顯著的差異。這些研究並不能直接拿來比較，因為劑量補充、成果報告及受試者的特徵(例如: 嚴重的肺部疾病、生長和營養狀態、胰臟功能不全)有所不同。在這兩個研究中沒有不良反應事件。第三個研究(只有摘要)以胰臟功能不全的孩子和年輕人，比較每天補充0.25毫克或0.5毫克的活性維生素D3及安慰劑，但只有治療前的數據可以取得。

作者結論

受限於受試者人數太少無法提出有利或有害的根據，所以應該先遵從相關的囊狀纖維化患者補充維生素D的治療準則，直到有更多的證據為止。

翻譯人

本摘要由臺灣大學附設醫院簡純青翻譯。

此翻譯計畫由臺灣國家衛生研究院(National Health Research Institutes, Taiwan)統籌。

總結

在囊狀纖維化的孩童與成人常規使用維生素D補充 囊狀纖維化合併胰臟功能不全者因吸收不良而引起維生素D的缺乏。維生素D的缺乏可能會引起一些特殊的問題，像骨骼畸形、骨折，也可能會造成一般健康情況的惡化及呼吸系統的問題。因此，囊狀纖維化的患者通常很年輕時就開始規律補充維生素D，但是過多的維生素D也可能導致呼吸系統的問題及鈣離子濃度過高。這文獻的回溯包含三個臨床試驗，但只能從兩個試驗中取得實驗數據。我們無法獲得關於囊狀纖維化患者補充維生素D的益處與壞處的證據。作者目前無法得到是否該常規的補充維生素D的結論，因此建議在有進一步證據前，先依照當地的治療準則實施維生素D補充治療。