PhD project Stress-in-Action: Genes-stress interplay and cardiometabolic health

The Lifelines Cohort Study includes roughly 167,000 individuals from the north of the Netherlands [8, 9], and includes genome-wide genetic data as well as evaluations of cardiometabolic health outcomes and stress-related exposures, which are variables of interest in our study. The exact number of individuals required for the analysis will be determined by a number of criteria, including the effect sizes of the interactions of interest, the required statistical power, and the distribution of stress-related exposures and genetic vulnerability among Lifelines Cohort Study participants.  
The sample size should be large enough to provide enough statistical power while also ensuring the robustness of the results. Due to the vast age range of the multigenerational cohort study population, population stratification can be helpful to fully assess stress-related exposures, genetic susceptibility, and cardiometabolic health outcomes across different age groups.

Individuals with varying cardiometabolic health outcomes will be included in the research population, including those with hypertension, diabetes, obesity, dyslipidemia, and other pertinent cardiometabolic disorders. Individuals with varied amounts of cardiovascular risk factors, such as high blood pressure or aberrant lipid profiles, may also participate. It should be noted that the precise inclusion criteria, sample size needs, data availability (or gaps in data), and participant characteristics may be modified further throughout the study's planning and design phase. Stress-related exposures will be measured using self-report questionnaires filled out by individuals for the gene-environment correlation calculation from the LifeLines cohort.
Wang et al. (2023) [10] investigated the effect of genetic vulnerability in depression and anxiety using a similar strategy. The project produced a polygenic risk score by combining the Long-term Difficulties Inventory (LDI), the List of Threatening Events (LTE), childhood trauma, loneliness, and social support. The LTE was a 12-item self-report questionnaire meant to measure the frequency of stressful life events experienced in the preceding year, with individuals answering "no" or "yes" for each item. The results varied from zero (no occurrences) to twelve (12 events). To quantify stressful living events in the last two years, 13-item parent-report questionnaires with a "no" or "yes" response for each item were utilized for children. The children's ratings of stressful life experiences were normalized to correspond to the adult scale (0-12 points). Rosmalen et al. (2012) established that the LDI and LTE had adequate validity and stability to be included in large epidemiological cohort studies [14].