The first sample was collected at 08:00 AM after overnight fasting. The samples were collected around the clock at four-hour intervals. For more participants characteristics and individual data, see S1 Table. The mean weight was 84.1 ☑3.9 kg for the males and 58.5 ☑3.6 kg for the females. The mean age of the males was 24.9 ± 7.2 years and 21.7 ± 0.5 years for the female volunteers. Inclusion criteria were:-age over 21 years old,-apparently healthy without any acute or chronic disease (general medical examination without laboratory analyses),-not taking any drugs, multivitamins and/or supplements, -non-smoking,-not more than 1 (for women) or 2 (for men) alcoholic beverages per day,-no shiftwork and have a normal circadian rhythm (sleeping at nighttime). Samples of 17 healthy volunteers, 10 women and 7 men were analyzed in this study. I also confirm that all information that I provided with regards to my general health condition and lifestyle is correct”. This was provided in Macedonian and the translation would be as follows: "I confirm that I am informed about the goals of the Circadian study and voluntary participate in it. All participants signed an informed written consent. We determined cortisol levels and clock gene expression levels in blood throughout the day to study diurnal variation of these classical markers in a routine setting.Īpproval for all procedures was obtained from the ethical committee of the Goce Delchev University in Stip, Republic of Macedonia. In addition, classical markers to study circadian rhythms in chronobiology research are measured: cortisol and components of the molecular biological clock i.e. The aim of the present study was to investigate diurnal variation of a set of markers (relevant for metabolic disorders and hormone-associated cancers) in a routine setting in males and females, resembling molecular epidemiology studies: namely, non-fasted and limited control for other environmental influences. Therefore, most molecular epidemiology studies collect blood samples to study biomarkers for adverse health outcomes without standardization for time-point, food intake or sleep. Due to the large-scale set up of some molecular epidemiology studies, the possibility for standardization of sample collection to time of day and food consumption is limited. Most information on diurnal variation is derived from these controlled laboratory studies in which factors influencing diurnal variation (such as food intake and/or sleep/wake cycle) are controlled (for example see references ). The diurnal variation of various blood markers has previously been studied in different settings, ranging from a relatively uncontrolled routine setting to very tightly controlled laboratory settings. In this study, we determine whether a set of biomarkers relevant for metabolic disorders and hormone-associated cancers, consisting of endocrine and sex hormones and lipids, shows diurnal variation. When the diurnal variation is larger than the inter-individual variation, time of day should be taken into account in molecular epidemiology studies. This might render accurate determination of markers in molecular epidemiology studies challenging. For example, previous studies have indicated that there are substantial changes in the blood transcriptome after experiencing insufficient or mistimed sleep. Importantly, heterogeneity in diurnal variation and disturbance of circadian rhythms among a study population might increasingly occur as a result of our increasing 24/7 economy and related variation in exposure to environmental factors (such as light and food). Several markers are well known for their diurnal variation, for example cortisol and melatonin. However, environmental factors, such as light exposure and food intake might affect the levels of these markers, since they provide input for the internal time-keeping system. In general, for these markers sampling can occur at any time-point during the day or after an overnight fast. Metabolic markers might serve as important (early) indicators for metabolic disorders, including cardiovascular diseases and type 2 diabetes, and hormonal disbalance is often studied in large epidemiological settings since these are associated with high incidence cancers, such as breast cancer. Many molecular epidemiology studies focusing on high prevalent diseases, such as metabolic disorders and cancer, make use of metabolic and hormonal markers (for examples see references.
0 Comments
Leave a Reply. |
Details
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |