Genetic analysis of physical activity in twins

BACKGROUND: The reduced contribution of physical activity (PA) to daily energy expenditure contributes to the increased prevalence of obesity. A genetic control of activity-induced energy expenditure (AEE) may contribute to a genetic susceptibility to obesity. OBJECTIVE: Our aim was to investigate the relative contribution of genetic and environmental factors to the variation and covariation in AEE and PA. DESIGN: Twelve monozygotic and 8 same-sex dizygotic (including 2 same-sex sibling pairs; age differences: 2 and 2.5 y) twin pairs aged between 18 and 39 y participated. AEE was measured in a respiration chamber for 24 h and with doubly labeled water in daily life for 2 wk. PA was recorded simultaneously with a triaxial accelerometer. Structural equation modeling was used to separate and quantify the observed variance into sex-adjusted additive genetic and common and unique environmental contributions. RESULTS: In the respiration chamber, common and unique environmental factors explained the variance in AEE and PA, and no genetic contribution was found. In daily life, genetic factors explained 72% of the variance in AEE and 78% of the variance in PA. Unique environmental factors explained the remaining variance. The same additive genetic factors explained 67% of the covariance in AEE and PA in daily life. CONCLUSIONS: In the present exploratory study that used gold standard measurements for AEE and PA but a limited sample size, genetic influence explained a large part of the variation in AEE and PA in daily life, whereas both AEE and PA were influenced by environment only within the confined area of the respiration chamber

Heritability and genetic etiology of habitual physical activity: a twin study with objective measures

Twin studies with objective measurements suggest habitual physical activity (HPA) are modestly to highly heritable, depending on age. We aimed to confirm or refute this finding and identify relevant genetic variants using a candidate gene approach. HPA was measured for 14 days with a validated triaxial accelerometer (Tracmor) in two populations: (1) 28 monozygotic and 24 dizygotic same-sex twin pairs (aged 22 ± 5 years, BMI 21.8 ± 3.4 kg/m(2), 21 male, 31 female pairs); (2) 52 and 65 unrelated men and women (aged 21 ± 2 years, BMI 22.0 ± 2.5 kg/m(2)). Single nucleotide polymorphisms (SNPs) in PPARD, PPARGC1A, NRF1 and MTOR were considered candidates. Association analyses were performed for both groups separately followed by meta-analysis. Structural equation modeling shows significant familiality for HPA, consistent with a role for additive genetic factors (heritability 57 %, 95 % CI 32–74 %, AE model) or common environmental factors (47 %, 95 % CI 23–65 %, CE model). A moderate heritability was observed for the time spent on low- and high-intensity physical activity (P ≤ 0.05), but could not be confirmed for the time spent on moderate-intensity physical activity. For PPARD, each additional effect allele was inversely associated with HPA (P ≤ 0.01; rs2076168 allele C) or tended to be associated with HPA (P ≤ 0.05; rs2267668 allele G). Linkage disequilibrium existed between those two SNPs (alleles A/G and A/C, respectively) and meta-analysis showed that carriers of the AAGC haplotype were less physically active than carriers of the AAAA and AA AC haplotypes combined (P = 0.017). For PPARGC1A, carriers of AA in rs8192678 spent more time on high-intensity physical activity than GG carriers (P = 0.001). No associations were observed with SNPs in NRF1 and MTOR. In conclusion, HPA may be modestly heritable, which is confirmed by an association with variants in PPARD

Experiences of resuming life after immunotherapy and associated survivorship care needs:A qualitative study among patients with metastatic melanoma

BACKGROUND: Immune checkpoint inhibitors (ICIs) have significantly improved the overall survival of patients with metastatic melanoma. It is unclear how the growing group of metastatic melanoma survivors resume their lives after treatment, and which needs they have regarding survivorship care (SSC). OBJECTIVES: To gain an in-depth understanding of metastatic melanoma survivors' experiences of resuming life after ICIs and their associated SSC needs. METHODS: A qualitative study was conducted among 20 patients with metastatic melanoma in whom ICIs had been discontinued after ongoing tumour response. One focus group (n = 9) was held, which was complemented by 11 individual interviews. Purposive sampling was used to select a variable sample in terms of sex, age, time since discontinuation of ICIs, and perceived impact of the disease. A topic guide was used to structure the (group) interviews, which were transcribed verbatim and analysed in a thematic content analysis, using several phases of coding. RESULTS: In resuming life after ICIs, the prognosis switch often caused mixed feelings among patients, mainly because of the uncertainty about the future. Demands and expectations from self and others, persistent complaints and new problems in different life domains often make it challenging to proceed with life as it was prior to metastatic cancer. Patients indicated they needed to find a new balance, which included learning to cope with uncertainty and a changed perspective on life and close relationships. In terms of SSC needs, patients particularly stressed the need for more tailored patient information, available at one location. In addition, they emphasized the need to know who to turn to in case of questions and indicated the need for psychosocial support, also for their close relatives. CONCLUSIONS: Metastatic melanoma survivors face various challenges in resuming life after ICIs and are left with several unmet SSC needs. Efforts should be focused on offering psychosocial supportive care in addition to medical care, from diagnosis onwards, taking into account the patient's close relatives. A single point of contact and personalized survivorship care plan (SCP) could be of added value in guiding them through the patient journey, which is, given its multidisciplinary nature, particularly important in melanoma care. What is already known about this topic? Since the introduction of immune checkpoint inhibitors (ICIs) the overall survival of patients with metastatic melanoma has improved significantly, leading to a growing group of melanoma survivors. Melanoma survivors may face various problems and challenges in resuming life after treatment, which may be associated with unmet survivorship care (SSC) needs. An in-depth understanding of their experiences with resuming life and the associated SSC needs is currently lacking. What does this study add? Metastatic melanoma survivors experience various challenges after immunotherapy, from the uncertain prognosis switch to the struggle of finding a new balance in life. Besides negative aspects, such as complaints in different life domains, the patient journey is often accompanied by positive outcomes, for example a changed perspective on life. They stress the need for tailored patient information and broader supportive care, also for their close relatives. What are the clinical implications of this work? In addition to medical care, efforts should be focused on offering psychosocial supportive care, including return-to-work issues, from diagnosis onwards, ideally taking into account the patient's close relatives. To guide them through the patient journey, a single point of contact and a personalized survivorship care plan (SCP) could be of added value. The latter is particularly important in melanoma care, given its multidisciplinary nature

The PPARgamma ligand rosiglitazone influences triacylglycerol metabolism in non-obese males, without increasing the transcriptional activity of PPARgamma in the subcutaneous adipose tissue

PPARgamma is obligatory for fat mass generation and is thought to determine the amount of TAG stored per fat cell. We investigated whether ligand availability for PPARgamma is rate limiting in fat mass generation and substrate metabolism. Twenty healthy men (20-29 years) were randomly assigned to receive the PPARgamma ligand rosiglitazone (RSG) (8 mg/d) (n 10) or a placebo (n 10) during a stay of 7 d in a respiration chamber. Food intake was ad libitum, resulting in positive energy balances of 32.2 MJ (placebo) and 44.7 MJ (RSG). Fat cell size and expression of PPARgamma, adipocyte fatty acid-binding protein (aP2), adipsin, adiponectin and fasting-induced adipose factor (FIAF) were determined in subcutaneous abdominal fat biopsies. The total amount of fat stored and the amount of TAG per fat cell were not different between groups. For the entire group, fat cell size was decreased after overeating (P = 0.02). FIAF mRNA levels were decreased after overeating in the RSG group (P = 0.01), with a trend towards a decrease in the placebo group. Unexpectedly, RSG treatment did not influence the expression levels of PPARgamma and of the PPARgamma responsive genes aP2, adiponectin and adipsin. In addition, RSG resulted in a larger increase in plasma TAG during overeating than placebo treatment. These results suggest that in healthy, non-obese males the PPARgamma ligand RSG influences TAG metabolism, independent of its PPARgamma transcriptional activity in the subcutaneous adipose tissue

High-sensitivity cardiac troponin t: Risk stratification tool in patients with symptoms of chest discomfort

BACKGROUND: Recent studies have demonstrated the association between increased concentrations of high-sensitivity cardiac troponin T (hs-cTnT) and the incidence of myocardial infarction, heart failure, and mortality. However, most prognostic studies to date focus on the value of hs-cTnT in the elderly or general population. The value of hs-cTnT in symptomatic patients visiting the outpatient department remains unclear. The aim of this study was to investigate the prognostic value of hs-cTnT as a biomarker in patients with symptoms of chest discomfort suspected for coronary artery disease and to assess its additional value in combination with other risk stratification tools in predicting cardiac events. METHODS: We studied 1,088 patients (follow-up 2.2 +/- 0.8 years) with chest discomfort who underwent coronary calcium scoring and coronary CT-angiography. Traditional cardiovascular risk factors and concentrations of hs-cTnT, N-terminal pro-brain-type natriuretic peptide (NT-proBNP) and high-sensitivity C-reactive protein (hsCRP) were assessed. Study endpoint was the occurrence of late coronary revascularization (>90 days), acute coronary syndrome, and cardiac mortality. RESULTS: Hs-cTnT was a significant predictor for the composite endpoint (highest quartile [Q4]>6.7 ng/L, HR 3.55; 95%CI 1.88-6.70; P<0.001). Survival analysis showed that hs-cTnT had significant predictive value on top of current risk stratification tools (Chi-square change P<0.01). In patients with hs-cTnT in Q4 versus <Q4, a 2- to 3-fold increase in cardiovascular risk was noticed, either when corrected for high or low Framingham risk score, coronary calcium scoring, or CT-angiography assessment (HR 3.11; 2.73; 2.47; respectively; all P<0.01). This was not the case for hsCRP and NT-proBNP. CONCLUSIONS: Hs-cTnT is a useful prognostic biomarker in patients with chest discomfort suspected for coronary artery disease. In addition, hs-cTnT was an independent predictor for cardiac events when corrected for cardiovascular risk profiling, calcium score and CT-angiography results

High-sensitivity cardiac troponin t: Risk stratification tool in patients with symptoms of chest discomfort

BACKGROUND: Recent studies have demonstrated the association between increased concentrations of high-sensitivity cardiac troponin T (hs-cTnT) and the incidence of myocardial infarction, heart failure, and mortality. However, most prognostic studies to date focus on the value of hs-cTnT in the elderly or general population. The value of hs-cTnT in symptomatic patients visiting the outpatient department remains unclear. The aim of this study was to investigate the prognostic value of hs-cTnT as a biomarker in patients with symptoms of chest discomfort suspected for coronary artery disease and to assess its additional value in combination with other risk stratification tools in predicting cardiac events. METHODS: We studied 1,088 patients (follow-up 2.2 +/- 0.8 years) with chest discomfort who underwent coronary calcium scoring and coronary CT-angiography. Traditional cardiovascular risk factors and concentrations of hs-cTnT, N-terminal pro-brain-type natriuretic peptide (NT-proBNP) and high-sensitivity C-reactive protein (hsCRP) were assessed. Study endpoint was the occurrence of late coronary revascularization (>90 days), acute coronary syndrome, and cardiac mortality. RESULTS: Hs-cTnT was a significant predictor for the composite endpoint (highest quartile [Q4]>6.7 ng/L, HR 3.55; 95%CI 1.88-6.70; P<0.001). Survival analysis showed that hs-cTnT had significant predictive value on top of current risk stratification tools (Chi-square change P<0.01). In patients with hs-cTnT in Q4 versus <Q4, a 2- to 3-fold increase in cardiovascular risk was noticed, either when corrected for high or low Framingham risk score, coronary calcium scoring, or CT-angiography assessment (HR 3.11; 2.73; 2.47; respectively; all P<0.01). This was not the case for hsCRP and NT-proBNP. CONCLUSIONS: Hs-cTnT is a useful prognostic biomarker in patients with chest discomfort suspected for coronary artery disease. In addition, hs-cTnT was an independent predictor for cardiac events when corrected for cardiovascular risk profiling, calcium score and CT-angiography results

Experiences of resuming life after immunotherapy and associated survivorship care needs: A qualitative study among patients with metastatic melanoma

Background Immune checkpoint inhibitors (ICIs) have significantly improved the overall survival of patients with metastatic melanoma. It is unclear how the growing group of metastatic melanoma survivors resume their lives after treatment, and which needs they have regarding survivorship care (SSC). Objectives To gain an in-depth understanding of metastatic melanoma survivors’ experiences of resuming life after ICIs and their associated SSC needs. Methods A qualitative study was conducted among 20 patients with metastatic melanoma in whom ICIs had been discontinued after ongoing tumour response. One focus group (n = 9) was held, which was complemented by 11 individual interviews. Purposive sampling was used to select a variable sample in terms of sex, age, time since discontinuation of ICIs, and perceived impact of the disease. A topic guide was used to structure the (group) interviews, which were transcribed verbatim and analysed in a thematic content analysis, using several phases of coding. Results In resuming life after ICIs, the prognosis switch often caused mixed feelings among patients, mainly because of the uncertainty about the future. Demands and expectations from self and others, persistent complaints and new problems in different life domains often make it challenging to proceed with life as it was prior to metastatic cancer. Patients indicated they needed to find a new balance, which included learning to cope with uncertainty and a changed perspective on life and close relationships. In terms of SSC needs, patients particularly stressed the need for more tailored patient information, available at one location. In addition, they emphasized the need to know who to turn to in case of questions and indicated the need for psychosocial support, also for their close relatives. Conclusions Metastatic melanoma survivors face various challenges in resuming life after ICIs and are left with several unmet SSC needs. Efforts should be focused on offering psychosocial supportive care in addition to medical care, from diagnosis onwards, taking into account the patient’s close relatives. A single point of contact and personalized survivorship care plan (SCP) could be of added value in guiding them through the patient journey, which is, given its multidisciplinary nature, particularly important in melanoma care