Statistical methods to assess and minimize the role of intra-individual variability in obscuring the relationship between dietary lipids and serum cholesterol

doi:10.1016/0021-9681(78)90004-8

Journal of Chronic Diseases

Volume 31, Issues 6–7, 1978, Pages 399-418

Journal of Chronic D...

https://doi.org/10.1016/0021-9681(78)90004-8 Get rights and content

Abstract

Investigations involving comparisons of populations, as well as intervention studies on groups, both under free-living and metabolic ward conditions, unequivocally demonstrate significant relationships between lipid components of the diet and serum cholesterol levels. However, low order or no correlations have been reported when these dietary variables and serum cholesterol are related for individuals. Several factors underlie this apparent paradox. This paper discusses at length the role of intra-individual variation in this apparent paradox, with particular emphasis on the errors caused by intra-individual variation in classification and estimation of correlation coefficients. Methods are presented for estimating the number of measurements required to achieve a suitable degree of accuracy for both classification and correlation analysis. Based on these theoretical considerations and practical examples illustrating their application, an assessment is made of commonly used dietary survey methods in terms of their appropriateness for measuring individual dietary intake. Suggestions are made for improving the design and methods of nutritional surveys, especially with regard to reducing errors introduced by intra-individual variation.

References (44)

R.O. West et al.
Diet and serum cholesterol levels
Am J Clin Nutr
(1968)
D.M. Hegsted et al.
Quantitative effect of dietary factors on serum cholesterol in man
Am J Clin Nutr
(1965)
F.H. Mattson et al.
Effect of dietary cholesterol on serum cholesterol in man
Am J Clin Nutr
(1972)
A. Keys et al.
Diet and serum cholesterol in man: lack of effect of dietary cholesterol
J Nutr
(1956)
J.L. Tillotson et al.
Epidemiology of coronary heart disease and stroke in Japanese men living in Japan, Hawaii and California: methodology for comparison of diet
Am J Clin Nutr
(1973)
A.B. Nichols et al.
Daily nutritional intake and serum lipid levels. The Tecumseh Study
Am J Clin Nutr
(1976)
G.V. Mann et al.
Diet and cardiovascular disease in the Framingham Study: I. Measruement of dietary intake
Am J Clin Nutr
(1962)
R.L. Huenemann et al.
Methods of dietary investigation
J Am Diet Assoc
(1942)
C.M. Young et al.
A comparison of dietary study methods: I. Dietary history vs seven-day-record
J Am Diet Ass
(1952)
T.R. Dawber et al.
Dietary assessment in the epidemiologic study of coronary heart disease: The Framingham Study—2. Reliability of measurement
Am J Clin Nutr
(1962)

F.W. Chalmers et al.

The dietary record—how many and which days?

J Am Diet Ass

(1952)

J.H. Hankin et al.

A short dietary method for epidemiologic studies—2, Variability of measured nutrient intakes

Am J Clin Nutr

(1967)

M. Balogh et al.

Random repeat 24-hour dietary recalls

Am J Clin Nutr

(1971)

A. Keys

Coronary heart disease in seven countries

Circulation

(1970)

F.M. Sacks et al.

Plasma lipids and proteins in vegetarians and controls

New Engl J Med

(1975)

A. Keys et al.

Serum cholesterol response to changes in the diet, 1–5

Metabolism

(1965)

W.E. Connor

Dietary cholesterol and the pathogenesis of atherosclerosis

Geriatrics

(1961)

W.E. Connor et al.

Effect of dietary cholesterol upon serum lipids in man

J Lab Clin Med

(1961)

W.E. Connor et al.

The serum lipids in men receiving high cholesterol and cholesterol-free diets

J clin Invest

(1961)

W.E. Connor et al.

The interrelated effects of dietary cholesterol and fat upon human serum lipid levels

J clin Invest

(1964)

B.A. Erickson et al.

The effect of partial hydrogenation on dietary fats, of the ratio of polyunsaturated to saturated fatty acids, and of dietary cholesterol upon plasma lipids in man

J clin Invest

(1964)

D.B. Stone et al.

The prolonged effects of a low cholesterol, high carbohydrate diet upon the serum lipids in diabetic patients

Diabetes

(1963)

Cited by (460)

A validation study comparing energy and nutrient intake between a web-based food frequency questionnaire and a 4-d dietary record
2024, Nutrition
Reliable assessments of dietary intake is crucial when examining associations between dietary factors and different outcomes. Today, web-based instead of paper-based food frequency questionnaires (FFQs) are common. A web-based FFQ implies a different experience (including design differences, the possibility only to show relevant questions, and automatic checks for completeness) and may capture dietary intake differently. The aim of this study was to validate a well-used paper-based FFQ transferred to a web-based version against a 4-d dietary record.
Baseline data from a dietary intervention study comprising women and men with type 2 diabetes were used. Diet was assessed with the web-based FFQ and a 4-d dietary record. Energy intake and energy-adjusted nutrient intakes were assessed and compared using Spearman's rank correlation and Bland–Altman analysis. The analysis included 101 participants.
The average energy intake with the FFQ was 2068 kcal, 157 kcal higher than the average from the dietary record. Significant deattenuated correlations were found for intake of energy (r = 0.37; 95% confidence interval [CI],0.19–0.53), carbohydrates (r = 0.85; 95% CI, 0.78–0.89), protein (r = 0.53; 95% CI, 0.38–0.66) and fat (r = 0.59; 95% CI, 0.44–0.70). Significant deattenuated correlations (ranging r = 0.26–0.73) were found for intake of alcohol, whole grain, fiber, saturated fat, monounsaturated fat, polyunsaturated fat, cholesterol, vitamins A, B₁₂, C, D, and E, folate, iron, potassium, magnesium, and calcium. Bland–Altman analyses showed no clear trends but wide limits of agreement.
Overall, the web-based FFQ performed well and is similar to the paper-based version. It can be a useful tool for dietary assessments.
Effects of sleep quality on diurnal variation of brain volume in older adults: A retrospective cross-sectional study
2024, NeuroImage
Brain volume is influenced by several factors that can change throughout the day. In addition, most of these factors are influenced by sleep quality. This study investigated diurnal variation in brain volume and its relation to overnight sleep quality.
We enrolled 1,003 healthy Koreans without any psychiatric disorders aged 60 years or older. We assessed sleep quality and average wake time using the Pittsburgh Sleep Quality Index, and divided sleep quality into good, moderate, and poor groups. We estimated the whole and regional brain volumes from three-dimensional T1-weighted brain MRI scans. We divided the interval between average wake-up time and MRI acquisition time (INT) into tertile groups: short (INT₁), medium (INT₂), and long (INT₃).
Whole and regional brain volumes showed no significance with respect to INT. However, the `interaction between INT and sleep quality showed significance for whole brain, cerebral gray matter, and cerebrospinal fluid volumes (p < .05). The INT₂ group showed significantly lower volumes of whole brain, whole gray matter, cerebral gray matter, cortical gray matter, subcortical gray matter, and cerebrospinal fluid than the INT₁ and INT₃ groups only in the individuals with good sleep quality.
Human brain volume changes significantly within a day associated with overnight sleep in the individuals with good sleep quality.
Dietary fat quality, plasma atherogenic lipoproteins, and atherosclerotic cardiovascular disease: An overview of the rationale for dietary recommendations for fat intake
2024, Atherosclerosis
The scientific evidence supporting the current dietary recommendations for fat quality keeps accumulating; however, a paradoxical distrust has taken root among many researchers, clinicians, and in parts of the general public. One explanation for this distrust may relate to an incomplete overview of the totality of the evidence for the link between fat quality as a dietary exposure, and health outcomes such as atherosclerotic cardiovascular disease (ASCVD). Therefore, the main aim of the present narrative review was to provide a comprehensive overview of the rationale for dietary recommendations for fat intake, limiting our discussion to ASCVD as outcome. Herein, we provide a core framework – a causal model – that can help us understand the evidence that has accumulated to date, and that can help us understand new evidence that may become available in the future. The causal model for fat quality and ASCVD is comprised of three key research questions (RQs), each of which determine which scientific methods are most appropriate to use, and thereby which lines of evidence that should feed into the causal model. First, we discuss the link between low-density lipoprotein (LDL) particles and ASCVD (RQ1); we draw especially on evidence from genetic studies, randomized controlled trials (RCTs), epidemiology, and mechanistic studies. Second, we explain the link between dietary fat quality and LDL particles (RQ2); we draw especially on metabolic ward studies, controlled trials (randomized and non-randomized), and mechanistic studies. Third, we explain the link between dietary fat quality, LDL particles, and ASCVD (RQ3); we draw especially on RCTs in animals and humans, epidemiology, population-based changes, and experiments of nature.
Additionally, the distrust over dietary recommendations for fat quality may partly relate to an unclear understanding of the scientific method, especially as applied in nutrition research, including the process of developing dietary guidelines. We therefore also aimed to clarify this process. We discuss how we assess causality in nutrition research, and how we progress from scientific evidence to providing dietary recommendations.
Contribution to the understanding of how principal component analysis–derived dietary patterns emerge from habitual data on food consumption
2018, American Journal of Clinical Nutrition
Principal component analysis (PCA) is a widely used exploratory method in epidemiology to derive dietary patterns from habitual diet. Such dietary patterns seem to originate from intakes on multiple days and eating occasions. Therefore, analyzing food intake of study populations with different levels of food consumption can provide additional insights as to how habitual dietary patterns are formed.
We analyzed the food intake data of German adults in terms of the relations among food groups from three 24-h dietary recalls (24hDRs) on the habitual, single-day, and main-meal levels, and investigated the contribution of each level to the formation of PCA-derived habitual dietary patterns.
Three 24hDRs were collected in 2010–2012 from 816 adults for an European Prospective Investigation into Cancer and Nutrition (EPIC)–Potsdam subcohort study. We identified PCA-derived habitual dietary patterns and compared cross-sectional food consumption data in terms of correlation (Spearman), consistency (intraclass correlation coefficient), and frequency of consumption across all days and main meals. Contribution to the formation of the dietary patterns was obtained through Spearman correlation of the dietary pattern scores.
Among the meals, breakfast appeared to be the most consistent eating occasion within individuals. Dinner showed the strongest correlations with “Prudent” (Spearman correlation = 0.60), “Western” (Spearman correlation = 0.59), and “Traditional” (Spearman correlation = 0.60) dietary patterns identified on the habitual level, and lunch showed the strongest correlations with the “Cereals and legumes” (Spearman correlation = 0.60) habitual dietary pattern.
Higher meal consistency was related to lower contributions to the formation of PCA-derived habitual dietary patterns. Absolute amounts of food consumption did not strongly conform to the habitual dietary patterns by meals, suggesting that these patterns are formed by complex combinations of variable food consumption across meals. Dinner showed the highest contribution to the formation of habitual dietary patterns. This study provided information about how PCA-derived dietary patterns are formed and how they could be influenced.
Within-person, between-person and seasonal variance in nutrient intakes among 4- to 8-year-old rural Zambian children
2020, British Journal of Nutrition
Validation of a semi-quantitative FFQ for 18-month-old toddlers: The Growing Up in Singapore Towards Healthy Outcomes (GUSTO) study
2019, Public Health Nutrition

View all citing articles on Scopus

View full text

Statistical methods to assess and minimize the role of intra-individual variability in obscuring the relationship between dietary lipids and serum cholesterol

Abstract

Am J Clin Nutr

Am J Clin Nutr

Am J Clin Nutr

J Nutr

Am J Clin Nutr

Am J Clin Nutr

Am J Clin Nutr

J Am Diet Assoc

J Am Diet Ass

Am J Clin Nutr

J Am Diet Ass

Am J Clin Nutr

Am J Clin Nutr

Coronary heart disease in seven countries

Circulation

Plasma lipids and proteins in vegetarians and controls

New Engl J Med

Serum cholesterol response to changes in the diet, 1–5

Metabolism

Dietary cholesterol and the pathogenesis of atherosclerosis

Geriatrics

Effect of dietary cholesterol upon serum lipids in man

J Lab Clin Med

The serum lipids in men receiving high cholesterol and cholesterol-free diets

J clin Invest

The interrelated effects of dietary cholesterol and fat upon human serum lipid levels

J clin Invest

The effect of partial hydrogenation on dietary fats, of the ratio of polyunsaturated to saturated fatty acids, and of dietary cholesterol upon plasma lipids in man

J clin Invest

The prolonged effects of a low cholesterol, high carbohydrate diet upon the serum lipids in diabetic patients

Diabetes