TirolGESUND: Baseline-controlled Comparison of the Effects of Fasting Dietary Intervention or Smoking Cessation Combined With Exercise in Healthy Female Tyrolean Volunteers Aged 30-60 on Epigenetic and Multi-omic Biomarkers of Health, Ageing, and Disease

Background and study aims: A recent study reported that a majority of malignancies may be caused modifiable risk factors and could therefore be prevented. Smoking and diet are known risk factors for cancer but also other disorders such as cardiovascular or metabolic disorders and neurodegeneration, and may promote premature cellular ageing. The investigators and others have recently described epigenetic signatures for risk of being diagnosed, or developing future, women's cancers, as well as signatures reflecting cellular ageing and exposure to risk factors such as smoking. Utilization of DNA methylation biomarkers as surrogate endpoints indicative of current and/or future disease risk could improve future efforts in preventive medicine, both by providing information on disease risk and biofeedback. Few longitudinal studies have so far investigated the effects of lifestyle changes on DNA methylation and other biomarkers of health and disease.

TirolGESUND investigates the effect of two lifestyle interventions, smoking cessation or intermittent fasting (both with additional optional exercise), over 6 months for the promotion of health and reduction of disease risk, focusing on women's cancers.

Hypothesis: Intermittent fasting or smoking cessation for a duration of 6 months result in a modulation of scores of disease risk- and age-associated DNA methylation biomarker signatures in cervical samples, indicating a reduction of disease risk, exposure, or cellular ageing.

Study design: TirolGESUND is a baseline-controlled intervention study with two parallel arms, smoking cessation and intermittent fasting. Participants are allocated to the study arm based on eligibility criteria. Within the intermittent fasting arm, participants are randomised to receive a ketogenic supplement or not. Ketosis has been suggested to elicit beneficial metabolic alterations and could therefore further enhance beneficial effects in the dietary intervention.

Endpoints: The primary endpoint are score changes in epigenetic biomarkers of cellular ageing and disease risk, primarily recently published Women's cancer risk identification (WID) indices.

In secondary and subsidiary outcomes, the study will explore temporal and spatial dynamics of DNA methylation alterations in response to lifestyle interventions, comparing different surrogate samples (blood, buccal, cervical).

The study also investigates the impact of lifestyle intervention on other biomarkers of health and disease as a pilot study for future behavioural studies in the space of disease prevention and ageing research.

Intervention: Participants will be allocated to intermittent fasting or smoking cessation based on inclusion criteria. Intermittent fasting encompasses a 16:8 intermittent fasting schedule. Food intake is limited to an 8 h window per day with fasting for the remaining 16 h. Within the intermittent fasting study, participants are randomised to receive a ketogenic supplement (medium-chain triglyceride fibre) or not. Participants in the smoking cessation study will be guided to stop smoking. All participants will receive 1:1 personal coaching throughout the study, and will be provided with an optional exercise programme. All participants will also receive nutritional advice from a professional dietician throughout the study.

The duration of the study including intervention is 6 months for each participant. Participants are invited to return for optional sample collection visits at 12 and 18 months.

Visits and examinations: The following samples will be collected at baseline and subsequently every two months for 6 months: cervical, buccal, blood, fecal, urine and saliva samples. At the beginning and end of the study, participants will additionally receive sports medicine examinations (spirometry, ergometry/sports medicine exam) and an examination of vascular health. Participants are asked to complete an epidemiological questionnaire at the beginning of the study and receive additional questionnaires throughout the study to monitor food intake (prior to every visit), physical activity (once a month), or quality of life (baseline, 6 months). Participants may optionally donate skin biopsies at baseline and after 6 months.

Participants receive a fitness tracker to monitor physical activity and exercise in an objective manner. Some participants in the intermittent fasting group are receiving a capillary blood monitor to evaluate ketosis levels at the end of the fasting period three times a week.

Randomization in the intermittent fasting study arm: Participants are randomised to receive or to not receive ketogenic supplement 1:1 using menopause- and BMI-stratified block randomization.

Participant risks and benefits: Participants will receive support in implementing (putative) health-promoting interventions, including giving up smoking and intermittent fasting over 6 months, and are hence expected to personally benefit from participation. Risks are expected to be minimal as the study involves only a behavioural/lifestyle change, but can include e.g. development of haematoma after blood sampling, mood swings due to smoking cessation, or hunger at the initiation of intermittent fasting.

Sample size: Dynamics of DNA methylation changes are unknown at the start of the study, rendering sample size estimation challenging. For each study arm (intermittent fasting, intermittent fasting plus ketogenic supplement, smoking cessation) n=60 participants are recruited based on prior information of standard deviation in DNA methylation indices.

Expected Drop-Out levels: Based on prior literature in lifestyle or dietary interventions, drop-out rates of 15-20% are expected.

Data management and protection: Clinical data is recorded using an electronic case report form with validity checks. Laboratory data is analysed in a coded manner. Data protection follows the principles of the European General Data Protection Regulation (GDPR).

Quality control: Standard operating procedures for sample collection and clinical procedures have been designed and implemented.

Inclusion criteria

• Women aged 30 to 60
• Motivated to change their lifestyle

Smoking cessation intervention:

3a. Smoking cessation: ≥10 cigarettes per day for at least the last five years

Dietary intervention:

3b Dietary intervention: BMI between 25 and 35

NB [Nota Bene], should 3a and 3b apply, participant will be allocated to the smoking cessation intervention.

Exclusion criteria

• Relevant underlying conditions:

• Current or previous malignant tumour or cancer
• Current or previous significant cardiovascular disorder [participants with elevated blood pressure are allowed to participate as long as it is well controlled under their current medication]
• Current or previous metabolic disorder (e.g., diabetes type I or II) [in the dietary intervention arm, participants with current hypothyroidism/Morbus Hashimoto will be excluded as the switch to intermittent fasting may require a adjustment of their medication]
• Current or previous psychiatric disorder (e.g., eating disorder, depression)
• Current pregnancy or lactation period
• Total hysterectomy
• Known current or previous premalignant lesion of the cervix uteri (CIN2/3)
• Concurrent participation in another interventional trial