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J Pryer

Publications and source records attributed to J Pryer.

8 recordsLinked to original sources
PubMed2000

The problem of accuracy in dietary surveys. Analysis of the over 65 UK National Diet and Nutrition Survey.

STUDY OBJECTIVE: To investigate the prevalence and nature of low energy reporting in a dietary survey of British adults over 65 years of age. DESIGN: Randomly selected cross sectional sample of 2060 British adults over 65 years. Four day weighed food diaries and questionnaires on health, lifestyle and socioeconomic characteristics. SETTING: Great Britain. PARTICIPANTS: 539 women and 558 men over 65 years who were free living and completed four day food diaries. MAIN RESULTS: A high proportion of men and women were classified as low energy reporters (LERs). Reported consumption of full fat dairy products, sugar and sweet foods, and alcoholic drinks differed most between LERs and non-LERs. Among LERs, reported protein and starch intakes were higher, fat, sugar and alcohol intakes were lower. LERs of either sex were more likely to be obese, male LERs were also more likely to belong to the manual social classes. CONCLUSIONS: The high level of low energy reporting probably resulted from a coalescence of factors such as the weighed diary methodology and a reluctance to report consumption of unhealthy foods. The use of validatory biomarkers such as doubly labelled water needs to be more widespread.

Aged↗
PubMed1996

Dietary calcium and blood pressure: a meta-analysis of randomized clinical trials.

PURPOSE: To assess the effect of dietary calcium supplementation on blood pressure. DATA SOURCES: Published reports of trials studying the effect of dietary calcium supplementation on blood pressure were identified by a search of previous reviews, a MEDLINE search, a manual review of journal articles, and a review of abstracts from scientific meetings. STUDY SELECTION: Randomized clinical trials in which dietary calcium intake varied by intervention group were selected. Multifactorial trials were not included. DATA SYNTHESIS: Data from 28 active treatment arms or strata from 22 randomized clinical trials were pooled using a weighted average method, with weights proportional to the inverse of the variance of the treatment effect. The total sample comprised 1231 persons. Because trials of both normotensive and hypertensive persons were included, subgroup analyses could be done. Pooled estimates of the effect of calcium supplementation on blood pressure were -0.18 mm Hg for diastolic blood pressure (95% CI, -0.75 to 0.40 mm Hg) and -0.89 mm Hg for systolic blood pressure (CI, -1.74 to -0.05 mm Hg). Pooled estimates for systolic blood pressure were -0.53 mm Hg (CI, -1.56 to 0.49 mm Hg) for trials of normotensive persons and -1.68 mm Hg (CI, -3.18 to -0.18 mm Hg) for trials of hypertensive persons. Diastolic blood pressure was not significantly affected in either subgroup. CONCLUSION: The pooled estimate shows a statistically significant decrease of systolic blood pressure with calcium supplementation, both for hypertensive persons and for the overall sample. However, the effect is too small to support the use of calcium supplementation for preventing or treating hypertension.

Adult↗
PubMed1995

Epidemiologic association between dietary calcium intake and blood pressure: a meta-analysis of published data.

The objectives of the study were to assess whether the epidemiologic data support a relation between dietary calcium intake and blood pressure, to obtain a quantitative estimate of the difference in blood pressure for a given difference in dietary calcium intake, and to assess the public health implications. A meta-analysis of published data (January 1983 to November 1993) that investigated the association between dietary calcium intake and blood pressure in different populations around the world was performed. Of 63 population studies identified, 23 were suitable for a quantitative overview (total n = 38,950). Unadjusted regression coefficients (95% confidence intervals) were obtained. Pooled unadjusted regression coefficients (95% confidence intervals) were then computed weighting each individual study by the inverse of its variance. Tests of heterogeneity and sensitivity analysis were carried out, and the possibility of publication bias was assessed. The regression coefficients ranged between -9.40 and 1.63 mmHg/100 mg calcium for systolic blood pressure and between -4.90 and 0.47 for diastolic blood pressure. In men (11 studies, n = 7,271), the pooled regression coefficients were -0.010 and -0.009 mmHg/100 mg calcium for systolic and diastolic pressures, respectively (p < 0.001 and p < 0.05). In women (six studies, n = 8,507), they were -0.15 and -0.057 mmHg/100 mg calcium (p < 0.001 and p < 0.02), and in men and women combined (six studies, n = 23,172 for systolic pressure and four studies, n = 3,215 for diastolic pressure) they were -0.061 and -0.061 mmHg/100 mg calcium (p < 0.001 and p < 0.05). In those studies that used the 24-hour recall method, the pooled regression coefficients were -0.06 and -0.09 mmHg/100 mg calcium (p < 0.005 and p = 0.07), whereas in those that used the food frequency questionnaire, they were -0.15 and -0.05 mmhg/100 mg calcium (p < 0.001 and p < 0.03). These data are consistent with an inverse association between dietary calcium intake and blood pressure. However, the size of the estimate, the observed heterogeneity among studies, and the possibility of confounding and publication bias indicate that an increase in calcium intake above the Recommended Dietary Allowance is not recommended at population level for the prevention and treatment of high blood pressure.

Adult↗
PubMed1995

Dietary calcium and blood pressure: a review of the observational studies.

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)

Adolescent↗
PubMed1994

Fat intake: implications of changes in distribution for setting dietary goals in the UK.

STUDY OBJECTIVE: To examine (a) changes in the shape of the distribution of dietary fat intake as the mean dietary fat intake of the population shifts and (b) implications for setting national dietary goals. DESIGN: Data on the percentage of energy from total fat, saturates, monounsaturates, polyunsaturates, and the P:S ratio were analysed for two dietary intervention trials and six cross sectional dietary surveys. The nutrient distributions from each study were described in terms of the mean, standard deviation (SD), coefficient of variation (CV), and skewness statistic. For the intervention trials statistical parameters were compared for groups who received and did not receive dietary advice. For the cross sectional studies, statistical parameters were compared across groups with different levels of mean fat intake. The implications of the results for setting dietary goals were considered using statistical models. MAIN RESULTS: For most fat fractions there was a positive association between the mean and the SD, and an inverse association between the mean and the CV, indicating that as the mean shifts upwards the SD increases but not in proportion to the mean. This is intermediate between a constant SD and a constant CV model. For a population nutrient goal of a maximum of 15% saturates, the estimated population mean for British women would be 8.4% using the constant SD model and 10.8% using the constant CV model. For saturates and the P:S ratio, a lower mean intake was associated with a greater positive skew in the distribution of reported intakes. For saturates, this is consistent with a group of high fat consumers who fail to reduce their intake as the population mean shifts downwards: a "rearguard effect". Findings for the P:S ratio are consistent with a group of consumers who produced a strong positive skew at low mean intakes, which reduced in size as the mean population intake increases: a "vanguard effect". CONCLUSIONS: These findings provide evidence that the distribution of fat intake may change with the mean to a degree that the setting and monitoring of nutritional goals may need to take account of changes in variance and shape of the intake distribution.

Adult↗