Revisiting the hypothesis of syndromic frailty: a cross-sectional study of the structural validity of the frailty phenotype.

BACKGROUND: Fried's Phenotype Model of Frailty (PMF) postulates that frailty is a syndrome. Features of a syndrome are a heterogeneous population that can be split into at least two classes, those presenting and those not presenting the syndrome. Syndromes are characterized by a specific mixture of signs and symptoms which increase in prevalence, from less to more severe classes. So far, the null hypothesis of homogeneity - signs and symptoms of frailty cannot identify at least two classes - has been tested using Latent Class Analysis (LCA) on the five dichotomized components of PMF (unintentional weight loss, exhaustion, weakness, slowness, and low physical activity). The aim of this study is to investigate further the construct validity of frailty as a syndrome using the extension offered by Factor Mixture Models (FMM). METHODS: LCA on dichotomized scores and FMM on continuous scores were conducted to test homogeneity on the five PMF components in a sample of 1643 community-dwelling older adults living in Québec, Canada (FRéLE). RESULTS: With dichotomized LCA, three frailty classes were found: robust, prefrail and frail, and the hypothesis of homogeneity was rejected. However, in FMM, frailty was better represented as a continuous variable than as latent heterogeneous classes. Thus, the PMF measurement model of frailty did not meet the features of a syndrome in this study. CONCLUSION: Using the FRéLE cohort, the PMF measurement model validity is questioned. Valid measurement of a syndrome depends on an understanding of its etiological factors and pathophysiological processes, and on a modelling of how the measured components are linked to these processes. Without these features, assessing frailty in a clinical setting may not improve patient health. Research on frailty should address these issues before promoting its use in clinical settings.

A framework for measurement and harmonization of pediatric multiple sclerosis etiologic research studies: The Pediatric MS Tool-Kit.

BACKGROUND: While studying the etiology of multiple sclerosis (MS) in children has several methodological advantages over studying etiology in adults, studies are limited by small sample sizes. OBJECTIVE: Using a rigorous methodological process, we developed the Pediatric MS Tool-Kit, a measurement framework that includes a minimal set of core variables to assess etiological risk factors. METHODS: We solicited input from the International Pediatric MS Study Group to select three risk factors: environmental tobacco smoke (ETS) exposure, sun exposure, and vitamin D intake. To develop the Tool-Kit, we used a Delphi study involving a working group of epidemiologists, neurologists, and content experts from North America and Europe. RESULTS: The Tool-Kit includes six core variables to measure ETS, six to measure sun exposure, and six to measure vitamin D intake. The Tool-Kit can be accessed online ( www.maelstrom-research.org/mica/network/tool-kit ). CONCLUSION: The goals of the Tool-Kit are to enhance exposure measurement in newly designed pediatric MS studies and comparability of results across studies, and in the longer term to facilitate harmonization of studies, a methodological approach that can be used to circumvent issues of small sample sizes. We believe the Tool-Kit will prove to be a valuable resource to guide pediatric MS researchers in developing study-specific questionnaire.

A prospective evaluation of the depression-nutrient intake reverse causality hypothesis in a cohort of community-dwelling older Canadians.

Studies have investigated the potential protective effects that diet may have on late-life depression incidence. This disorder can, however, affect the person's food intake, widely known as the reverse causality hypothesis of depression. To test this hypothesis, we compared mean nutrient intakes from three 24-h recalls during the year depression was detected (Geriatric Depression Scale ≥11 or antidepressant medication) with intakes from 1 year earlier among community-dwelling older adults (67-83 years) followed up annually in the 4-year Québec Longitudinal Study on Nutrition and Aging, who were free of depression and cognitive impairment at baseline. Participants (n 158, 64·4 % female) who became depressed and had data available for all follow-up years were matched by age group and sex with non-depressed participants. General linear mixed models were adjusted for percentage changes in physical activity, functional autonomy and stressful life events reported at the time of positive screening. A significant group effect for the dietary intake of all three B-vitamins was observed, as depression cases had consistently lower dietary intakes than controls (P<0·01). Over time, intakes of dietary vitamin B12 declined within depressed participants in bivariate analysis, but there was no time×group effect for any nutrient tested in the multivariate analyses. Intakes of energy, protein, saturated fat and total dietary fibre did not change in cases v. CONTROLS: Among community-dwelling older adults, declines in dietary vitamins B6, B12 and folate may precede depression incidence. To help preventative efforts by programmes and practitioners, longitudinal cohorts of longer duration should investigate the extent of the decline in dietary intakes relative to the time of depression.

Energy and protein intakes and their association with a decline in functional capacity among diabetic older adults from the NuAge cohort.

PURPOSE: Diabetic older adults (OA) are at greater risk of muscle strength (MS) loss and functional capacity (FC) decline than non-diabetics. Protein and energy intakes are important determinants of muscle mass and MS maintenance and indirectly affect FC. The study sought to determine whether low protein and energy intakes were associated with FC decline and whether this association was mediated by MS in diabetic OA over a 3-year follow-up, in secondary analyses of the Quebec Longitudinal Study on Nutrition and Successful Aging. METHODS: In 172 diabetic OA (62 % men, mean age = 75 years), FC decline was defined as the change between SMAF (Système de Mesure de l'Autonomie Fonctionnelle) scores at baseline (T1) and 3 years later (T4). Baseline adequate protein and energy intakes were set at ≥1 g/kg BW and ≥30 kcal/kg BW, respectively. Sex-stratified linear regressions were controlled for confounding variables. RESULTS: Mean body weight (BW) was 85.42 ± 13.8 in men and 79.7 ± 11.5 in women (p ≤ .001). Adequate protein intake in women was associated with lesser FC decline (mean ± SE) (2.11 ± 0.81 vs. 4.91 ± 0.72; p = .029), while adequate energy intake was not associated with FC decline either in men or in women. In women, 1 g protein/kg BW helped maintain MS, hence minimizing FC decline. CONCLUSIONS: These results demonstrate that protein intake is important in maintaining FC in diabetic OA, albeit with sex differences. This study provides further evidence that protein requirements may be greater than the 0.8 g/kg BW currently recommended for OA. Future research in larger samples over longer follow-up is needed to confirm these results.

Individual and collective factors predicting change in diet quality over 3 years in a subset of older men and women from the NuAge cohort.

PURPOSE: This study examined individual and collective factors as predictors of change in global diet quality (DQ). METHODS: Subjects were 373 older adults (57 % female) aged 68-82 years at recruitment (T1) into the NuAge Cohort Study, and followed for three years. Data were collected by questionnaires, physical performance tests and anthropometric measurements. Diet was assessed at T1 and T4 using three non-consecutive 24-h diet recalls (24HR) and DQ (Canadian Healthy Eating Index), and was computed on the means of the 24HR. DQ change over three years was determined as "DQT4-DQT1". Baseline (T1) measures significantly correlated with DQ at T1 were entered into backward stepwise linear regression analyses along with selected theoretical constructs and controlled for baseline DQ to determine predictors of change in DQ over 3 years. RESULTS: Among men, education (p = .009) and sensations of hunger (p = .01) were positive predictors of DQ change over time, while DQ at T1 (p < .0001), cognition (p = .003) and social network (p = .019) were negative predictors (adjusted R (2) = 30.4 %). Finally, among women, diet knowledge (p = .044) was a positive predictor of DQ change, while DQ at T1 (p < .0001) and social network (p = .033) were negative predictors of DQ change over 3 years (adjusted R (2) = 24.1 %). CONCLUSIONS: These results can inform dietary intervention programmes targeting gender-specific determinants of diet quality in older adults.

Protein intake protects against weight loss in healthy community-dwelling older adults.

Weight loss is prevalent in the elderly population, with deleterious health consequences, notably loss of lean body mass and subsequent functional decline. Protein intake below the current RDA [0.8 g/(kg · d)] is also common in older adults; however, the link between the 2 has received little attention. Our objective was to assess the relation between protein intake and incident 1-y weight loss ≥5% in community-dwelling older adults. We conducted a nested, prospective, case-control study in 1793 community-living elderly participants of the Quebec Longitudinal Study of Nutrition as a Determinant of Successful Aging (NuAge). We studied 211 incident cases of 1-y weight loss (≥5%) and 211 weight-stable controls (±2%) matched by sex and age category (70 ± 2, 75 ± 2, and 80 ± 2 y). Diet was measured by 3 nonconsecutive 24-h recalls. ORs (95% CIs) for the association between protein intake and weight loss were computed by using conditional logistic regression. After adjustment for body mass index, energy intake, appetite, smoking status, physical activity level, physical function, chronic diseases and medications, depressive symptoms, and serum albumin and ultrasensitive C-reactive protein, the ORs of weight loss in participants with low protein intakes [<0.8 g/(kg · d)] were 2.56 (95% CI: 1.01, 6.50) compared with participants with very high protein intakes [≥1.2 g/(kg · d)]. Corresponding numbers were 2.15 (95% CI: 1.02, 4.56) in participants with moderate protein intakes [0.8-<1.0 g/(kg · d)] and 1.33 (95% CI: 0.77, 2.28) in participants with high protein intakes [1.0-1.2 g/(kg · d)]. Our results suggest that protein intakes >1.0 g/(kg · d) are protective against weight loss in healthy older adults. These findings add epidemiologic evidence in support of higher optimal protein intakes than the current guidelines for healthy older adults.

Relationship between diet quality and cognition depends on socioeconomic position in healthy older adults.

Both diet quality and socioeconomic position (SEP) have been linked to age-related cognitive changes, but there is little understanding of how the socioeconomic context of dietary intake may shape its cognitive impact. We examined whether equal adherence to "prudent" and "Western" dietary patterns, identified by principal components analysis, was associated with global cognitive function [Modified Mini-Mental State Examination (3MS)] in independently living older adults with different SEPs (aged 68-84 y; n = 1099). The interaction of dietary pattern adherence with household income, educational attainment, occupational prestige, and a composite indicator of SEP combining all 3 was examined in multiple-adjusted mixed models over 3 y of follow-up in participants of the NuAge study (Quebec Longitudinal Study on Nutrition and Successful Aging). Adherence to the prudent pattern (vegetables, fruits, fish, poultry, and lower-fat dairy products) was related to higher 3MS scores at recruitment only in the upper categories of income [parameter estimate (B): 0.56; 95% CI: 0.11, 1.01], education (B: 0.44; 95% CI: 0.080, 0.80), or composite SEP (B: 0.37; 95% CI: 0.045, 0.70). High prudent pattern adherence was associated with less cognitive decline only in those with low composite SEP (B: 0.25; 95% CI: 0.0094, 0.50). Conversely, adherence to the Western pattern (meats, potatoes, processed foods, and higher-fat dairy products) was associated with more cognitive decline (B: -0.23; 95% CI: -0.43, -0.032) only in those with low educational attainment. In summary, among individuals with equivalent diet quality, the magnitude and characteristics of the diet-cognition relationship depended on their socioeconomic circumstances. These results suggest that interventions promoting retention of cognitive function through improved diet quality would provide maximum benefit to those with relatively low SEP.

A single measurement of serum phylloquinone is an adequate indicator of long-term phylloquinone exposure in healthy older adults.

Assessment of long-term phylloquinone exposure is challenging in studies investigating vitamin K in health. Data are equivocal as to whether a single measurement of circulating phylloquinone would be adequate. The primary purpose of the present study was to validate the use of a single measurement of serum phylloquinone as a surrogate for long-term phylloquinone exposure in healthy older adults. Using data from the Québec Longitudinal Study on Nutrition and Successful Aging, the objectives were to: 1) determine the reproducibility of circulating phylloquinone over 2 y (n = 234); 2) calculate how a single measurement would rank or classify individuals and attenuate the regression coefficient between circulating phylloquinone and a health outcome; and 3) investigate the association of a single measurement of serum phylloquinone with long-term phylloquinone intakes assessed over the year prior to the blood draw (n = 228). The variance analysis based on 2 blood samples showed a fair to good reproducibility for serum phylloquinone (intra-class correlation = 0.49). The correlation coefficient between the ranking of individuals based on a single measurement of circulating phylloquinone and the "true" ranking would be 0.70. The multiple regression analysis showed that long-term phylloquinone intake was the strongest predictor of serum phylloquinone (t = 4.94; P < 0.001). The partial correlation coefficient (r = 0.32) was comparable with those reported in studies where blood sampling and diet recording were juxtaposed and/or multiple blood samples were used. The present study provides evidence that the use of a single measurement of circulating phylloquinone is adequate for assessing long-term phylloquinone exposure in healthy older adults.

Associations between residential food environment and dietary patterns in urban-dwelling older adults: results from the VoisiNuAge study.

OBJECTIVE: To examine associations between the availability of residential-area food sources and dietary patterns among seniors. DESIGN: Cross-sectional analyses. Individual-level data from the NuAge study on nutrition and healthy ageing were merged with geographic information system data on food store availability and area-level social composition. Two dietary patterns reflecting lower- and higher-quality diets (respectively designated 'western' and 'prudent') were identified from FFQ data. Two food source relative availability measures were calculated for a 500 m road-network buffer around participants' homes: (i) proportion of fast-food outlets (%FFO) relative to all restaurants and (ii) proportion of stores potentially selling healthful foods (%HFS, healthful food stores) relative to all food stores. Associations between dietary patterns and food source exposure were tested in linear regression models accounting for individual (health and sociodemographic) and area-level (socio-economic and ethnicity) covariates. SETTING: Montréal metropolitan area, Canada. SUBJECTS: Urban-dwelling older adults (n 751), aged 68 to 84 years. RESULTS: %FFO was inversely associated with prudent diet (ß = -0·105; P < 0·05) and this association remained statistically significant in models accounting for %HFS. %HFS was inversely associated with lower western diet scores (ß = -0·124; P < 0·01). This latter association no longer reached significance once models were adjusted for area-level covariates. CONCLUSIONS: In Montréal, the food environment is related to the diet of older adults but these links are more complex than straightforward. The absence of significant relationships between healthful food stores and prudent diets, and between fast-food outlets and western diets, deserves further investigation.

Dietary resilience as described by older community-dwelling adults from the NuAge study "if there is a will -there is a way!".

Many older adults experience age-related changes that can have negative consequences for food intake. Some older adults continue to eat well despite these challenges showing dietary resilience. We aimed to describe the strategies used by older adults to overcome dietary obstacles and to explore the key themes of dietary resilience. The sample was drawn from the five-year Québec Longitudinal Study "NuAge". It included 30 participants (80% female) aged 73-87 years; 10 with decreased diet quality and 20 with steady or increased diet quality; all had faced key barriers to eating well. Semi-structured interviews explored how age-related changes affected participants' experiences with eating. Thematic analysis revealed strategies used to overcome eating, shopping, and meal preparation difficulties. Key themes of dietary resilience were: prioritizing eating well, doing whatever it takes to keep eating well, being able to do it yourself, getting help when you need it. Implications for health professionals are discussed.

A minimum of six days of diet recording is needed to assess usual vitamin K intake among older adults.

There is a growing interest in the role of vitamin K in health, especially in aging populations. Knowledge of inter- and intra-individual variability of dietary vitamin K intake could be useful to accurately assess usual intake and rank participants in epidemiological studies. Our objectives were to: 1) estimate the variance components of vitamin K intake; 2) investigate whether day of the week, season, and energy intake are factors related to intra-individual variance; and 3) calculate the requisite number of days to achieve desired degrees of accuracy for estimating individual vitamin K intake, ranking individuals and estimating regression coefficient. Vitamin K intake was assessed in 939 older adults (67-84 y) enrolled in the Québec Longitudinal Study on Nutrition and Successful Aging study using 2 sets of 3 nonconsecutive multiple-pass 24-h dietary recalls (24HR) collected 6 mo apart. Each set included 2 weekdays and one weekend day. Intra- to inter-individual variance ratios for vitamin K intake were 3.2 (95% CI = 2.6-3.9) overall, 2.6 (95% CI = 2.1-3.5) for men, and 3.7 (95% CI = 2.9-5.0) for women. Day of the week (weekdays) and season (May to October) were positively and significantly associated with vitamin K intake but explained a negligible part of intra-individual variation (<1%). Adjusting for energy intake explained <7% of variance and did not affect the variance ratio. Six to 13 24HR are required to properly rank individuals according to their usual vitamin K intake and limit attenuation of the regression coefficient. These results should be considered in studies planning to assess vitamin K intakes in older adults.

Relative validity of a food frequency questionnaire for pregnant women.

PURPOSE: Pregnant women's diets should be monitored to ensure adequacy, but few studies have assessed the validity of dietary assessment tools among pregnant women. We examined the relative validity of a self-administered, semiquantitative food frequency questionnaire (FFQ) adapted for use in the International Trial of Antioxidants in the Prevention of Preeclampsia for assessing usual diet during pregnancy. METHODS: A subsample (n=107) was recruited for the FFQ validation study, and provided three days of nonconsecutive three-day food records (3D-FRs) following completion of the FFQ. RESULTS: Mean ± standard deviation (median) energy intakes (kcal/kJ) from the FFQ and mean of 3D-FRs were 1963 ± 610 (1860)/8219 ± 2554 (7787) and 2320 ± 607 (2354)/9713 ± 2541 (9856), respectively. Spearman correlation coefficients between unadjusted FFQ and 3D-FRs nutrients were positive (rS ranged from 0.17 for iron to 0.49 for folate) and were generally statistically significant (0.05

Diet and prostate cancer risk with specific focus on dairy products and dietary calcium: a case-control study.

BACKGROUND: Despite the prevalence of prostate cancer worldwide, only a few risk factors have been well-established. The role of diet, especially of dairy products, in the etiology of prostate cancer is still controversial. METHODS: This study assessed the association of dietary components, particularly dairy products and dietary calcium, on prostate cancer risk in a case-control study of 197 cases and an equal number of individually matched controls recruited in Montreal, Canada. A semi-quantitative food frequency questionnaire was administered in which the usual consumption frequency and amounts consumed of more than 200 food items were recorded. RESULTS: We found a twofold increased risk of prostate cancer associated with an increased intake of dairy products {Odds Ratio (OR) = 2.19; 95% Confidence Intervals (CI) 1.22-3.94}. A significant trend of decreasing prostate cancer risk with higher intake was found for legumes, nuts, finfish/shellfish and for alpha-tocopherol after adjustment for calcium intake. Milk was the only dairy product significantly associated with prostate cancer risk, with OR = 2.27; 95% CI (1.25-4.09) for the highest versus lowest quartiles of consumption. Calcium, the main micronutrient contained in dairy products, showed only a borderline association with prostate cancer risk (P = 0.09), with slightly higher risk for higher calcium intake. In conclusion, this study supports the hypothesis that dairy products, especially milk, are involved in the etiology of prostate cancer. However, the mechanisms by which the various nutrients in dairy products and total diet may interact to influence this risk remain unknown.

An international trial of antioxidants in the prevention of preeclampsia (INTAPP).

OBJECTIVE: We sought to investigate whether prenatal vitamin C and E supplementation reduces the incidence of gestational hypertension (GH) and its adverse conditions among high- and low-risk women. STUDY DESIGN: In a multicenter randomized controlled trial, women were stratified by the risk status and assigned to daily treatment (1 g vitamin C and 400 IU vitamin E) or placebo. The primary outcome was GH and its adverse conditions. RESULTS: Of the 2647 women randomized, 2363 were included in the analysis. There was no difference in the risk of GH and its adverse conditions between groups (relative risk, 0.99; 95% confidence interval, 0.78-1.26). However, vitamins C and E increased the risk of fetal loss or perinatal death (nonprespecified) as well as preterm prelabor rupture of membranes. CONCLUSION: Vitamin C and E supplementation did not reduce the rate of preeclampsia or GH, but increased the risk of fetal loss or perinatal death and preterm prelabor rupture of membranes.

Examining the relative validity of an adult food frequency questionnaire in children and adolescents.

BACKGROUND AND OBJECTIVE: Dietary factors have been implicated in the pathogenesis of inflammatory bowel diseases (IBD). The aim of the study was to assess the accuracy of a food frequency questionnaire (FFQ) developed in French and English for adults 18 years and older, among subjects ages 7 to 18 years participating in a prospective cohort study. PATIENTS AND METHODS: Healthy children and adolescents ages 7 to 18 years were recruited from outpatient orthopedic clinics in a Montréal pediatric hospital. Of the 131 recruits, 65 (86% Francophone) provided a complete 78-item semiquantitative FFQ and 3-day nonconsecutive food records (3D-FR). Parents of young children completed both instruments, whereas older children and adolescents completed them on their own. The FFQ were analyzed using Microsoft Access software for customized data entry and the 3D-FR were analyzed using CANDAT software, both based on the 2007b Canadian Nutrient File. RESULTS: The FFQ overestimated intakes relative to the 3D-FR by around 15%. Spearman rank correlation coefficients between test and reference methods were positive, largely ranged from 0.22 (vitamin C) to 0.57 (saturated fat), and were generally statistically significant (0.05< P < 0.0001). Stronger associations between test and reference methods were found for adolescents (13-18 years) and for girls. Some 77% of participants were jointly classified into the same half of the distribution, with 39% exact agreement and only 6% frank misclassification. CONCLUSIONS: The FFQ can be confidently used to rank young subjects on a range of nutrient intakes with the potential to provide useful information on dietary risk factors in the etiology of inflammatory bowel disease. Accuracy could be enhanced by improving completion quality of FFQs, notably by young adolescent boys.

Risk of breast cancer among French-Canadian women, noncarriers of more frequent BRCA1/2 mutations and consumption of total energy, coffee, and alcohol.

Although the connection between diet, lifestyle and hormones suggests that nutritional and lifestyle factors may exert an influence in the etiology of breast cancer, it is not clear whether these factors operate in the same way in women without BRCA gene mutations. A nested case-control study was conducted in a cohort of French-Canadian women, with 560 members involving 280 nongene carriers of mutated BRCA gene affected by breast cancer and 280 nonaffected and nongene carriers of mutated BRCA gene. A validated semi-quantitative food frequency questionnaire was used to ascertain dietary intake, and a core questionnaire, to gather information on lifestyle risk factors. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated in logistic regression models. It was found that energy intake >2,057 Kcal/day was significantly and positively related to breast cancer risk (OR = 2.54; 95% CI: 1.67-3.84; p = 0.01). Women who drank more than eight cups of coffee per day had an increased risk of breast cancer: OR = 1.40 (95% CI: 1.09-2.24; p = 0.03). Subjects who drank >9 g of alcohol (ethanol) per day had an increased risk of breast cancer: OR = 1.55 (95% CI: 1.02-2.37; p = 0.04). In addition, a positive and significant association was noted between the consumption of beer, wine and spirits, and breast cancer risk. The ORs were 1.34 (95% CI: 1.28-2.11; p = 0.04) for more than two bottles of beer per week, OR = 1.16 (95% CI: 1.08-2.58; p = 0.05) for >10 oz of wine per week and OR = 1.09 (95% CI: 1.02-2.08; p = 0.05) for >6 oz of spirit per week, respectively. Intakes of other nutrients and dietary components were not significantly associated with nongene carrier breast cancer risk. This study provides evidence that total energy intake, coffee, and alcohol consumption may play a role in breast cancer risk.

Nutrient Patterns, Cognitive Function, and Decline in Older Persons: Results from the Three-City and NuAge Studies.

Dietary patterns, or the combination of foods and beverages intake, have been associated with better cognitive function in older persons. To date, no study has investigated the link between a posteriori nutrient patterns based on food intake, and cognitive decline in longitudinal analyses. The aim of this study was to evaluate the relationship between nutrient patterns and cognitive function and decline in two longitudinal cohorts of older persons from France and Canada. The study sample was composed of participants from the Three-City study (3C, France) and the Quebec Longitudinal Study on Nutrition and Successful Aging (NuAge, Quebec, Canada). Both studies estimated nutritional intakes at baseline, and carried out repeated measures of global cognitive function for 1,388 and 1,439 individuals, respectively. Nutrient patterns were determined using principal component analysis methodology in the two samples, and their relation with cognitive function and decline was estimated using linear mixed models. In 3C, a healthy nutrient pattern, characterized by higher intakes of plant-based foods, was associated with a higher global cognitive function at baseline, as opposed to a Western nutrient pattern, which was associated with lower cognitive performance. In NuAge, we also found a healthy nutrient pattern and a Western pattern, although no association was observed with either of these patterns in the Canadian cohort. No association between any of the nutrient patterns and cognitive decline was observed in either cohort. There is a need for longitudinal cohorts focusing on nutrient patterns with substantial follow-up, in order to evaluate more accurately associations between nutrition and cognition in older persons.

Low vitamin K intakes in community-dwelling elders at an early stage of Alzheimer's disease.

An increasing body of evidence points to a role for vitamin K in brain physiology through its participation in sphingolipid metabolism and biological activation of the vitamin K-dependent protein Gas6. One hypothesis is that vitamin K may also play a role in the pathogenesis of Alzheimer's disease. A recent study found that patients with early-stage Alzheimer's disease consumed less vitamin K than did cognitively intact control subjects. To learn more about the dietary intakes and food sources of vitamin K in these patients, a detailed analysis was conducted. Dietary vitamin K intakes were assessed from 5 nonconsecutive days of food records collected from 31 community-dwelling patients with early-stage Alzheimer's disease and in 31 age- and sex-matched cognitively intact control subjects. Mean vitamin K intake on a person-day basis was 63+/-90 microg/day in patients and 139+/-233 microg/day in control subjects. Vitamin K intakes were significantly less in participants with Alzheimer's disease (P<0.0001), even after adjusting for energy intakes (P=0.0003). Vegetables, fats, and fruits contributed more than 70% of total vitamin K intake in both groups. The main source of vitamin K was green vegetables, which contributed 33% and 49% to total intakes in patients and control subjects, respectively. This lower consumption of green vegetables in participants with Alzheimer's disease explained their lower vitamin K intakes overall. Despite their limitations, results are in line with the most recent research in both vitamin K and Alzheimer's disease and suggest a need to consider vitamin K in future investigations on the role of diet in Alzheimer's disease.

Validity and Reliability of a Short Diet Questionnaire to Estimate Dietary Intake in Older Adults in a Subsample of the Canadian Longitudinal Study on Aging.

This study assessed test-retest reliability and relative validity of the Short Diet Questionnaire (SDQ) and usability of an online 24 h recall among 232 participants (62 years ± 9.1; 49.6% female) from the Canadian Longitudinal Study on Aging (CLSA). Participants were asked to complete four 24 h dietary recalls (24HRs) using the Automated Self-Administered 24-h Dietary Assessment Tool (ASA24-Canada-2014), two SDQ administrations (prior to recalls one and four), and the System Usability Scale (SUS) for ASA24. For the SDQ administrations, Intraclass Correlation Coefficients ranged from 0.49 to 0.57 for nutrients and 0.35 to 0.72 for food groups. Mean intakes estimated from the SDQ were lower compared than those from the 24HRs. For nutrients, correlation coefficients were highest for fiber, calcium, and vitamin D (45⁻64 years: 0.59, 0.50, 0.51; >65 years: 0.29, 0.38, 0.49, p < 0.01); Kappas ranged from 0.14 to 0.37 in those 45⁻64 years and 0.17 to 0.32 in participants >65 years. Among the 70% who completed all recalls independently, the SUS indicated poor usability, though the majority reported feeling confident using ASA24. Overall, the SDQ captures intake with varying test-retest reliability and accuracy by nutrient and age. Further research is needed to inform use of a more comprehensive dietary measure in the CLSA.

Nutrition as a determinant of successful aging: description of the Quebec longitudinal study Nuage and results from cross-sectional pilot studies.

Optimal nutrition is essential for general well being, maintenance of physical and functional capacities and prevention of chronic disease in the elderly. The 5-year longitudinal study, NuAge, was designed to assess the pivotal role of nutrition on physical and cognitive status, functional autonomy and social functioning. A cohort of 1793 men and women, selected from three age groups (68-72, 73-77, 78-82) at recruitment, has been followed annually since 2003-2004. A plurimethodological approach, including basic, clinical, epidemiologic, and social research has been used. Data on various facets of nutritional status (diet, food habits, appetite, anthropometry and body composition), and functional (muscle strength, physical activity, physical and functional capacities and performance), medical (physical, mental and cognitive health, medication) and social data (network, support, participation) are collected by questionnaires or direct measurements. Blood, urine, and saliva samples are also collected and processed for genomic, transcriptomic, proteomic, and biochemical analyses and to study markers of endocrine, immune, and cognitive functions. Selected bio-psycho-social characteristics of the cohort, consumption of macronutrients, and biologic variables are presented, including the impact of intake of certain foods on total antioxidant status. Understanding the aging process as regulated by a modifiable factor such as nutrition should facilitate the development of targeted strategies for promoting successful aging.