Related Experiment Videos
Dietary calcium and blood pressure: a review of the observational studies
J Pryer1, F P Cappuccio, P Elliott
1Department of Public Health and Policy, London School of Hygiene and Tropical Medicine, UK.
Insights
Epidemiological data on dietary calcium intake and blood pressure (BP) show inconsistent results. While some studies suggest a slight inverse relationship, the overall evidence is inconclusive due to study design and reporting variations.
Area of Science:
- Nutrition Science
- Epidemiology
- Cardiovascular Health
Background:
- Observational studies have explored the link between dietary calcium and blood pressure (BP).
- Existing research presents inconsistencies in findings regarding this association.
- Calcium's role in cardiovascular health remains an area of active investigation.
Purpose of the Study:
- To evaluate the epidemiological evidence supporting a relationship between dietary calcium intake and blood pressure.
- To synthesize findings from published observational studies on calcium and BP.
- To identify patterns and inconsistencies in the reported associations.
Main Methods:
- Systematic review of 53 published observational studies from January 1983 to November 1993.
- Inclusion of studies from diverse geographical regions including the USA, Canada, Europe, and Asia.
- Analysis of data from 108 population samples and subgroups, utilizing methodologies like 24-hour dietary recall.
Main Results:
- Significant heterogeneity was observed in results within and between studies.
- Median regression coefficients indicated a small inverse association: -0.033 mm Hg/100 mg Ca for systolic BP and -0.140 mm Hg/100 mg Ca for diastolic BP.
- Incomplete data and methodological variations limited the assessment in many population samples.
Conclusions:
- The epidemiological data provide inconclusive evidence for a definitive relationship between dietary calcium intake and blood pressure.
- Variability in study designs, dietary assessment methods, and reporting practices contribute to the inconsistent findings.
- Further research with standardized methodologies may be needed to clarify the calcium-BP association.
Abstract:
The objective of this study was to assess whether the epidemiological data support a relation between dietary calcium intake and blood pressure (BP). Fifty three published reports of observational studies relating intake of calcium or calcium-rich foods to BP in the USA (n = 33), Canada (n = 3), Puerto Rico (n = 1), Europe (n = 9), Asia (n = 5), Australia (n = 1) and South Africa (n = 1) were identified including a Medline search (January 1983-November 1993). Sample size ranged from 55 to over 58,000 (median 885). Five studies were prospective, 48 cross-sectional, of which four also contained a longitudinal component. Various dietary methodologies were used; the most common was the 24 h dietary recall. Most studies controlled for age, sex and body mass index, with variable control for other confounders. Many reports also allowed identification of subgroups by sex, age and race. One hundred and eight population samples and subgroups could then be identified. There was inconsistency in results both within and between studies. In 12 of the 53 published reports simple regression coefficients were reported. Median regression coefficients were -0.033 mm Hg/100 mg Ca (range -4.90 to +/- 0.47; n = 12) for systolic blood pressure (SBP) and -0.140 mm Hg/100 mg Ca (range -9.40 to +1.63; n = 10) for diastolic blood pressure (DBP). The association between dietary calcium intake and BP could not be assessed in all 108 population samples and subgroups because of design features, incompleteness of reported results and methods of analysis.(ABSTRACT TRUNCATED AT 250 WORDS)