Calcium supplementation for prevention of primary hypertension.

CORMICK GABRIELA; CIAPPONI A

COCHRANE DATABASE OF SYSTEMATIC REVIEWS (ONLINE : UPDATE SOFTWARE)

JOHN WILEY & SONS LTD

Lugar: Londres; Año: 2012 p. 1 - 1

1469-493X

Hypertension is a major public health problem in both the developed and the developing world increasing the risk of cardiovascular and kidney diseases. The global prevalence of hypertension and high blood pressure are estimated to be 30% and 26% respectively Kearney, 2004 and high blood pressure has been estimated to increase to 29% by the year 2025. High blood pressure has been identified as the leading risk factor to mortality and the third leading risk factor for disease burden globally. In the year 2001, 7.6 million (13.5%) of all deaths were attributable to high blood pressure. While the prevalence of hypertension seems to be stabilizing or decreasing in the developed world, it is increasing in developing countries. Low-income and middle-income regions contribute to 80% of the attributable burden of disease affecting the younger age groups more than in high income countries. While chronic diseases have increased in these countries, undernutrition related problems such as micronutrient deficiencies still persist leaving a double burden of disease. These represent a challenge to develop interventions as excess and deficit nutritional problems have to be tackled within the same population and frequently within the same home. Several studies have shown an inverse association between calcium intake and blood pressure or hypertension. The hypothesis was originated by the observation that indigenous Guatemalan women showed low figures of PE-E and a high calcium intake due to the Mayan habit of treating corn with lime water.Based on this hypothesis a series of studies have been reported mainly in pregnant women, but also in children, and young and older adults. Due to the high frequency of hypertension, population based strategies to reduce blood pressure are more cost effective than individual strategies. Calcium supplementation or food fortification  are affordable interventions that if proven effective in reducing blood pressure, even in small levels, could have considerable impact at a population level. The effects on children and young people are of particular importance as pressure tends to track into adulthood. Williams2011 This review will explore the efficacy and safety of calcium supplementation or food fortification in reducing blood pressure and consequently in preventing hypertensive related problems in normotensive subjects of different age groups. It will look at the effect in reducing blood pressure in each population group and in preventing rather than treating hypertensive related problems. It will also provide more information of the effect of incrementing calcium intake on blood pressure of non pregnant women of reproductive age. Reviewing the effect of calcium in a normotensive population would be valuable to assess whether it could allow women to reach pregnancy with a lower range of blood pressure and a lower risk of developing pre-eclampsia or eclampsia. As there have been some concerns about adverse effects of calcium supplementation there is a need to assess adverse effects such as renal tract stone formation, impaired absorption of other minerals and increased cardiovascular events. Objective:To assess the efficacy and safety of calcium supplementation versus placebo or control for reducing blood pressure in normotensive subjects. Methods: All published unpublished and ongoing trials with random allocation to dietary calcium intervention such as supplementation or food fortification versus placebo or control. Quasi-random designs were excluded. Participants: Normotensive subjects of different age groups excluding pregnant women. Type of interventions:Interventions will include calcium supplementation using pills, tablets or sprinkle powder or any food or beverage fortified with calcium compared to placebo or control. Calcium fortification can include salt of calcium carbonate, sulphate, citrate, citrate malate, chloride, hydroxyapatite, phosphate, acetate, lactate, glycerophosphate, gluconate, oxide, or hydroxide. Calcium content in these salts varies from 9 to 70%. New Reference Studies with no placebo or control will be excluded. Interventions where calcium is combined with other macro or micronutrient to assess effects of both will be excluded.