Vitamin E (α- and γ-tocopherol) - determinants and associated outcomes

Vitamin E is a lipid-soluble vitamin encompassing different vitamin E forms (α-, β-, γ-, δ-tocopherols, and tocotrienols) with important anti-oxidative functions. There is limited knowledge regarding the distribution of plasma vitamin E concentrations in the general Northern German population, the relation of vitamin E to dietary patterns, and its association with cardiometabolic traits. Therefore, in this thesis, the distribution of both α- and γ-tocopherol levels was assessed in a sample from the general population; and biochemical and dietary correlates of vitamin E were explored. We observed, that nearly 60% of the Northern German population had adequate plasma α-tocopherol levels (>30 µmol/L), and that lipid traits and the intake of vitamin E supplementation were statistically significantly associated with circulating vitamin E levels. However, neither a priori nor a posteriori derived dietary patterns displayed an association with circulating α- and γ-tocopherol levels. Furthermore, we explored associations of plasma vitamin E levels with the following cardiometabolic traits: The metabolic syndrome (MetS), visceral (VAT) and subcutaneous (SAT) adipose tissue, liver signal intensity (LSI), fatty liver disease (FLD), and gallstone disease. The α-tocopherol/cholesterol ratio was positively associated with MetS and VAT; and the γ-tocopherol/cholesterol ratio was positively associated with MetS, VAT, and SAT. Lower odds of having gallstone disease were observed in the top (compared to the bottom) tertile of the plasma α-tocopherol/cholesterol ratio. All analyses were conducted using data from the first follow-up examination (2010-2012) of the PopGen control cohort, a population-based sample from Northern Germany. Populations based, prospective studies are warranted to confirm our results and to further explore the potential impact of the reported findings on other nutritional and health outcomes

Framework and baseline examination of the German National Cohort (NAKO)

The German National Cohort (NAKO) is a multidisciplinary, population-based prospective cohort study that aims to investigate the causes of widespread diseases, identify risk factors and improve early detection and prevention of disease. Specifically, NAKO is designed to identify novel and better characterize established risk and protection factors for the development of cardiovascular diseases, cancer, diabetes, neurodegenerative and psychiatric diseases, musculoskeletal diseases, respiratory and infectious diseases in a random sample of the general population. Between 2014 and 2019, a total of 205,415 men and women aged 19–74 years were recruited and examined in 18 study centres in Germany. The baseline assessment included a face-to-face interview, self-administered questionnaires and a wide range of biomedical examinations. Biomaterials were collected from all participants including serum, EDTA plasma, buffy coats, RNA and erythrocytes, urine, saliva, nasal swabs and stool. In 56,971 participants, an intensified examination programme was implemented. Whole-body 3T magnetic resonance imaging was performed in 30,861 participants on dedicated scanners. NAKO collects follow-up information on incident diseases through a combination of active follow-up using self-report via written questionnaires at 2–3 year intervals and passive follow-up via record linkages. All study participants are invited for re-examinations at the study centres in 4–5 year intervals. Thereby, longitudinal information on changes in risk factor profiles and in vascular, cardiac, metabolic, neurocognitive, pulmonary and sensory function is collected. NAKO is a major resource for population-based epidemiology to identify new and tailored strategies for early detection, prediction, prevention and treatment of major diseases for the next 30 years. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s10654-022-00890-5

Messung der körperlichen Fitness in der NAKO Gesundheitsstudie: Methoden, Qualitätssicherung und erste deskriptive Ergebnisse

Die körperliche Fitness ist das Maß für die individuelle Fähigkeit, körperlich aktiv zu sein. Ihre wesentlichen Komponenten sind die kardiorespiratorische Fitness (Cardiorespiratory Fitness, CRF), die Muskelkraft und die Beweglichkeit. Neben der körperlichen Aktivität ist die körperliche Fitness ein wesentlicher Prädiktor für Morbidität und Mortalität. Ziel der Arbeit sind die Beschreibung der Erhebungsmethoden körperlicher Fitness in der NAKO Gesundheitsstudie und die Darstellung erster deskriptiver Ergebnisse. In der NAKO-Basiserhebung wurden die maximale Handgreifkraft (Grip Strength, GS) und die CRF als Komponenten der körperlichen Fitness über ein Handdynamometer bzw. über einen Fahrradergometertest mit submaximaler Belastung erhoben. Daraus wurde die maximale Sauerstoffaufnahme (VO2max) zur Beurteilung der CRF abgeleitet. Die Ergebnisse von insgesamt 99.068 GS-Messungen und 3094 Messungen der CRF beruhen auf einem Datensatz zur Halbzeit der Basiserhebung der NAKO (Alter 20–73 Jahre, 47 % Männer). Männer zeigten im Vergleich zu Frauen höhere Werte der körperlichen Fitness (Männer: GS = 47,8 kg, VO2max = 36,4 ml·min−1 · kg−1; Frauen: GS = 29,9 kg, VO2max = 32,3 ml·min−1 · kg−1). Ungefähr ab dem 50. Lebensjahr konnte ein Rückgang der GS verzeichnet werden, wohingegen die CRF ab der Altersgruppe 20–29 Jahre bis zu den ≥60-Jährigen kontinuierlich abfiel. Die GS und die VO2max zeigten nach Korrektur für das Körpergewicht einen linear positiven Zusammenhang (Männer β = 0,21; Frauen β = 0,35). Die Analysen zeigten eine gute Übereinstimmung der Verteilung der körperlichen Fitness in der NAKO im Vergleich zu anderen bevölkerungsbasierten Studien. Zukünftige Auswertungen werden insbesondere die unabhängige Bedeutung der GS und CRF bei der Prädiktion von Morbidität und Mortalität beleuchten.Physical fitness is defined as an individual’s ability to be physically active. The main components are cardiorespiratory fitness (CRF), muscle strength, and flexibility. Regardless of physical activity level, physical fitness is an important determinant of morbidity and mortality. The aim of the current study was to describe the physical fitness assessment methodology in the German National Cohort (NAKO) and to present initial descriptive results in a subsample of the cohort. In the NAKO, hand grip strength (GS) and CRF as physical fitness components were assessed at baseline using a hand dynamometer and a submaximal bicycle ergometer test, respectively. Maximum oxygen uptake (VO2max) was estimated as a result of the bicycle ergometer test. The results of a total of 99,068 GS measurements and 3094 CRF measurements are based on a data set at halftime of the NAKO baseline survey (age 20–73 years, 47% men). Males showed higher values of physical fitness compared to women (males: GS = 47.8 kg, VO2max = 36.4 ml·min−1 · kg−1; females: GS = 29.9 kg, VO2max = 32.3 ml · min−1 · kg−1). GS declined from the age of 50 onwards, whereas VO2max levels decreased continuously between the age groups of 20–29 and ≥60 years. GS and VO2max showed a linear positive association after adjustment for body weight (males β = 0.21; females β = 0.35). These results indicate that the physical fitness measured in the NAKO are comparable to other population-based studies. Future analyses in this study will focus on examining the independent relations of GS and CRF with risk of morbidity and mortality

Association of Circulating Vitamin E (α- and γ-Tocopherol) Levels with Gallstone Disease

In addition to well-established risk factors like older age, female gender, and adiposity, oxidative stress may play a role in the pathophysiology of gallstone disease. Since vitamin E exerts important anti-oxidative functions, we hypothesized that circulating vitamin E levels might be inversely associated with prevalence of gallstone disease. In a cross-sectional study, we measured plasma levels of α- and γ-tocopherol using high performance liquid chromatography in a community-based sample (582 individuals; median age 62 years; 38.5% women). Gallstone disease status was assessed by ultrasound. Multivariable-adjusted logistic regression models were used to estimate the association of circulating α- and γ-tocopherol/cholesterol ratio levels with prevalent gallstone disease. Lower probabilities of having gallstone disease were observed in the top (compared to the bottom) tertile of the plasma α-tocopherol/cholesterol ratio in multivariable-adjusted models (OR (Odds Ratio): 0.31; 95% CI (Confidence Interval): 0.13–0.76). A lower probability of having gallstone disease was also observed for the γ-tocopherol/cholesterol ratio, though the association did not reach statistical significance (OR: 0.77; 95% CI: 0.35–1.69 for 3rd vs 1st tertile). In conclusion, our observations are consistent with the concept that higher vitamin E levels might protect from gallstone disease, a premise that needs to be further addressed in longitudinal studies

Postdiagnostic physical activity, sleep duration, and TV watching and all-cause mortality among long-term colorectal cancer survivors: a prospective cohort study

Background: Lifestyle recommendations for cancer survivors are warranted to improve survival. In this study, we aimed to examine the association of total physical activity, different types of physical activity, hours of sleeping at day and night, and hours spent watching television (TV) with all-cause mortality in long-term colorectal cancer (CRC) survivors. Methods: We assessed physical activity in 1376 CRC survivors (44% women; median age, 69 years) at median 6 years after CRC diagnosis using a validated questionnaire. Multivariable-adjusted Cox regression models were used to estimate hazard ratios (HRs) for all-cause mortality according to categories of physical activities, sleep duration, and TV watching. Results: During a median follow-up time of 7 years, 200 participants had died. Higher total physical activity was significantly associated with lower all-cause mortality (HR: 0.53; 95% CI: 0.36–0.80, 4th vs. 1st quartile). Specifically, sports, walking, and gardening showed a significant inverse association with all-cause mortality (HR: 0.34; 95% CI: 0.20–0.59, HR: 0.65; 95% CI: 0.43–1.00, and HR: 0.62; 95% CI: 0.42–0.91, respectively for highest versus lowest category). Individuals with ≥2 h of sleep during the day had a significantly increased risk of all-cause mortality compared to individuals with no sleep at day (HR: 2.22; 95% CI: 1.43–3.44). TV viewing of ≥4 h per day displayed a significant 45% (95% CI: 1.02–2.06) higher risk of dying compared to ≤2 h per day of watching TV. Conclusions: Physical activity was inversely related to all-cause mortality; specific activity types might be primarily responsible for this association. More hours of sleep during the day and a higher amount of TV viewing were each associated with higher all-cause mortality. Based on available evidence, it is reasonable to recommend CRC survivors to engage in regular physical activity. Electronic supplementary material The online version of this article (10.1186/s12885-017-3697-3) contains supplementary material, which is available to authorized users

Vitamin E (α- and γ-Tocopherol) Levels in the Community: Distribution, Clinical and Biochemical Correlates, and Association with Dietary Patterns

Little is known about the distribution and determinants of circulating vitamin E levels in a German population. In this cross-sectional study we assessed the distribution of both α- and γ-tocopherol levels, identified their clinical and biochemical correlates, and assessed their relationships with a priori and a posteriori derived dietary patterns. Plasma α- and γ-tocopherol concentrations were measured using high performance liquid chromatography (HPLC) with fluorescence detection in 641 individuals (mean-age: 61 years; 40.6% women). Correlates of both markers were determined using linear regression with backward selection. Using a validated food-frequency questionnaire (FFQ), an a priori defined vitamin E-rich dietary pattern was constructed, and three a posteriori derived dietary patterns were identified by principal component analysis. Each pattern was related to α- and γ-tocopherol levels using linear regression. Median concentrations of α- and γ-tocopherol were 31.54 μmol/L and 1.35 µmol/L, respectively. 57.6% of participants had α-tocopherol levels >30 µmol/L. Triglycerides, high density lipoprotein (HDL)- and low density lipoprotein (LDL)-cholesterol, and vitamin E supplementation were identified as correlates of vitamin E levels. After excluding supplement users, a dietary pattern rich in meat, bread, fats, potatoes, and sugar/confectionery was inversely related to α-tocopherol levels (β, −0.032, SE = 0.016; p = 0.047). Prospective studies are warranted to evaluate the actual impact of the reported findings in terms of nutrition and health outcomes