Energy Adjustment Methods for Nutritional Epidemiology: The Effect of Categorization

Brown, Charles; Kipnis, Victor; Freedman, Lawrence; Hartman, Anne M.; Schatzkin, Arthur; Wacholder, Sholom

doi:10.1093/oxfordjournals.aje.a117000

Cited by 128 publications

(67 citation statements)

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“…This theory is based on the assumption of using nutrient intake as a continuous variable. It is however common practice to categorise nutrient intakes, which removes the equivalencies between models (Brown et al, 1994;Willett et al, 1997). It has been observed that, when nutrient intake is expressed as categories, risk estimates from the nutrient residual and the nutrient density models become similar (Decarli et al, 1997;Kushi et al, 1992).…”

Section: Discussionmentioning

confidence: 99%

Fat intake is more strongly associated with lifestyle factors than with socio-economic characteristics, regardless of energy adjustment approach

et al. 2001

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Objective: To compare how three different energy adjustment approaches in¯uence the ranking of individuals on fat intake, and to examine the relation between fat intake and socio-economic, demographic and lifestyle characteristics for each energy adjustment approach. Design: A cross-sectional analysis project, using a sub-sample (7055 women and 3240 men) from the Malmo È Diet and Cancer Study. Dietary habits were assessed with an interview based diet history method. Fat intake was, depending on energy-adjustment method, de®ned as absolute intake (FATg), percentage energy from fat (FAT%), and residuals from total fat regressed on total energy (FATres). Cross-classi®cation compared categorisation into fat intake quintiles. Logistic regression estimated, separately for each of the three approaches, the associations between high fat intake and socio-economic, demographic and lifestyle characteristics. Results: Agreement in individuals' ranking was high between FAT% and FATres, but FATg differed substantially from the others. Current smoking, low level of leisure time physical activity and low alcohol intakes were, in multivariate analysis, consistently associated with risk of high fat consumption regardless of energy adjustment method. However, the associations with socio-economic characteristics varied with energy adjustment method and gender groups. Conclusions: The similarities between FAT% and FATres, in the ranking of individuals and in the association with lifestyle factors and socio-economic characteristics implies that it is possible to translate results obtained with FATres to recommendations using FAT%. The consistent lifestyle pattern across fat intake de®nitions (in energy adjusted models) may indicate that fat consumption is more strongly related to lifestyle factors than to socioeconomic characteristics.

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Section: Discussionmentioning

confidence: 99%

Fat intake is more strongly associated with lifestyle factors than with socio-economic characteristics, regardless of energy adjustment approach

et al. 2001

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“…Natural logarithmic transformation was applied for plasma folate and tHcy, and folate and energy intakes because these variables had a skewed distribution and the transformation improved the normality of the distribution. Folate intake was adjusted for energy intake by using the residual method (32 into the regression model and examined the significance of coefficients of the interaction term. To examine the associations among those with high risk levels of tHcy, we also performed similar analyses restricting subjects to those with tHcy levels higher than the reference range (13.5 nmol/mL, n520).…”

Section: Methodsmentioning

confidence: 99%

A Cross-Sectional Study to Find Out the Relationship of Methylenetetrahydrofolate Reductase (MTHFR) C677T Genotype with Plasma Levels of Folate and Total Homocysteine by Daily Folate Intake in Japanese

Fukuda

Hamajima

Wakai

et al. 2014

J Nutr Sci Vitaminol

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l-5-Methyl-tetrahydrofolate (THF), derived from dietary folate, is involved in the conversion of homocysteine into methionine ( Fig. 1; 1-3). Folate deficiency increases total homocysteine (tHcy) levels (4). Hyperhomocysteinemia is one of the risk factors of cardiovascular disease (4,5) and neural tube defects (NTDs) (6). Maintaining adequate blood folate levels and controlling tHcy levels are important in preventing these diseases.In the folate metabolic pathway, 5,10-methylene-THF is converted into 5-methyl-THF by the enzyme 10-methylene-THF reductase (MTHFR). In the MTHFR C677T polymorphism (rs 1801133), the T allele reduces thermostability of the enzyme and lowers its activity, which were found to be decreased by 30% in heterozygotes and by 65% in homozygotes of minor alleles compared with the CC genotype in an in vitro study (7). However, folate intake could increase blood folate levels even among those with the TT genotype. In previous observational studies, decreased tHcy levels were related to increased blood folate levels (8-11), and increased folate intake was associated with increased blood folate levels (8, 12) and decreased tHcy levels (8,13,14) in each of the MTHFR genotype. These correlations were substantially stronger among those with TT (8,9,[11][12][13][14][15] and those consuming relatively lower amounts of folate (8,12,13). In previous interventional studies using folate supplements or fortified foods, increased folate intake raised blood folate (16-21) and reduced tHcy levels (17-21).However, one study in Japan found no association of serum folate with energy-adjusted folate intake among those with the TT genotype (22). This may be partly explained by the difference in the amount of folate intake and sources of folate. The mean folate intake among Japanese aged 20 y or more was 329 mg/d for men and 189 mg/d for women and the mean intake from supplements or fortified foods among the population was only 1 mg/d in 2008 (23 (Received November 12, 2013) Summary In those with the methylenetetrahydrofolate reductase (MTHFR) 677TT genotype, enzyme activity is lowered. Therefore, these individuals might require an increased intake of folate to maintain or control blood levels of plasma folate or total homocysteine (tHcy). We examined associations of dietary folate intake with fasting plasma folate and total homocysteine (tHcy) according to genotype among 554 Japanese (207 men and 347 women aged 39-89 y) recruited in 2009. Intake of folate was estimated with a food frequency questionnaire. The MTHFR polymorphism was genotyped by a polymerase chain reaction with confronting two-pair primers. The log-transformed concentration of folate or tHcy was regressed on energy-adjusted folate intake in a linear regression analysis. Higher folate intake was associated with higher plasma folate among those with the CC (b50.165, p50.066) or CT (b50.248, p,0.001) genotypes, and with lower tHcy levels only among those with the CC (b520.141, p50.013) genotype. Plasma folate was significantly and inversely associat...

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“…We also adjusted for menopausal status (pre or post) and current use of female hormones (user or nonuser) in women only. Each dietary factor was adjusted by total energy with the use of the residual method (33)(34)(35) into the statistical model after log transformation. Isoflavone, miso soup, and soy food consumption were not included in the same models due to colinearity.…”

Section: Methodsmentioning

confidence: 99%

Dietary Soy and Isoflavone Intake and Risk of Colorectal Cancer in the Japan Public Health Center–Based Prospective Study

Akhter¹,

Inoue²,

Kurahashi³

et al. 2008

Cancer Epidemiology, Biomarkers &Amp; Prevention

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Several experimental studies have reported that the anticarcinogenic properties of dietary soy play an important role in preventing colorectal cancer. However, few epidemiologic studies have examined this association in general populations and their findings have been inconsistent. We investigated the association between dietary soy and isoflavone intake and incidence of colorectal cancer in a prospective cohort study of 83,063 Japanese men and women, ages 45 to 74 years. Dietary soy and isoflavone intake was measured through a validated food frequency questionnaire in 1995 and 1998. Throughout 2004, a total of 886 cases of colorectal cancer were newly identified (291 proximal colon, 286 distal colon, and 277 rectum). The hazard ratios and 95% confidence intervals (95% CIs) were estimated by fitting a Cox proportional hazards model.The intake of isoflavones, miso soup, and soy food was not associated with colorectal cancer in either men or women. By colorectal cancer subsite, the risk of proximal colon cancer in men decreased with increasing consumption of isoflavones, miso soup, and soy food. Compared with men in the lowest quartiles of isoflavones, miso soup, and soy food intake, the hazard ratios in the highest quartiles were 0.55 (95% CI, 0.33-0.92), 0.72 (95% CI, 0.43-1.21), and 0.51 (95% CI, 0.30-0.87), respectively. The results showed no association for distal colon and rectal cancer in men or for subsites of colorectal cancer in women. These findings suggest that the intake of isoflavones, miso soup, and soy food has no substantial effect on the risk of colorectal cancer in Japanese men and women. (Cancer Epidemiol Biomarkers Prev 2008;17(8):2128 -35)

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Energy Adjustment Methods for Nutritional Epidemiology: The Effect of Categorization

Cited by 128 publications

References 0 publications

Fat intake is more strongly associated with lifestyle factors than with socio-economic characteristics, regardless of energy adjustment approach

Fat intake is more strongly associated with lifestyle factors than with socio-economic characteristics, regardless of energy adjustment approach

A Cross-Sectional Study to Find Out the Relationship of Methylenetetrahydrofolate Reductase (MTHFR) C677T Genotype with Plasma Levels of Folate and Total Homocysteine by Daily Folate Intake in Japanese

Dietary Soy and Isoflavone Intake and Risk of Colorectal Cancer in the Japan Public Health Center–Based Prospective Study

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