Air Pollution Reduction in the Elderly and Cardiovascular and Cognitive Outcomes (ELIFA)

1. Study Population and Design

   Persons living in ''service flats'' or retirement homes are healthy elderly who respectively live semi-independently or dependently. The elderly homes will be located in Flanders, Belgium. Persons are included if they are 65 years or older, not bedridden, non- smoker and able to give informed consent. This selection is made on the basis of the mental state of candidate participants, this primary selection is based on the advice of the directors or head nurses of the elderly homes.

   A documented minimental state examination (MMSE) will be performed and the participation of the candidates will depend on a priori determined criteria (score 23) and the ability of the possible participant to perform the NES tests (cognitive test), done a priori of enrolment. The project design is an intervention study of in total 6 weeks, starting with a baseline pre-purification period, a 2-week active purification period and a 2-week post purification period. Each participant is his/her own control, excluding confounding by factors that are stable within an individual over time but vary between participants.

   The device (GENANO tubes, GENANO Benelux; Heusen-Zolder, België) is placed in the living room of each apartment during the study period. These kinds of air purification devices are used in medical settings (cleanrooms, medical practice) and give us the opportunity to create a well-controlled experimental real life setting.

   Ultra fine particle (UFP) (Aerasense, Philips), PM10-2.5 and total suspended particulates (TSP) (Aerocet, MetOne) are monitored. Blood and urine are sampled every week in the morning at the same hour per participant to avoid problems due to diurnal variation. The participants will be asked to fill in a questionnaire. For the duration of the study, the investigators ask the participants to keep their windows closed.

2. Primary Endpoints The primary endpoints focus on changes in the cardiovascular en neurobiological function.

   2.1 Cardiovascular function. The cardiovascular measurements are conducted non-invasively and are wide ranging in order to comprehensively study these effects.

   2.1.1. Microvasculature: After pupillary dilation, digital images of both the retinas are obtained using a digital retinal camera (Canon CR-2 Digital Retinal Camera).

   2.1.2. Macro vasculature: The distensibility and intermedia thickness of the carotid artery are measured by echo-graphical imaging with the esaote MY LAB ™ ONE mobil device.

   2.1.3.Heart rate variability: With a mobile ECG sensor (Biopatch, Zephyr) the heart rate variability (HRV) is continuously monitored for several 24h periods during the 3 phases of the study.

   2.1.4. Blood pressure: Using Stabil-O-Graph devices the blood pressure is determined 5 consecutive times for every time point.

   2.2 Cognitive function The investigators assess the neurobehavioral function with the Neurobehavioral Evaluation System (NES-3). Neurobehavioral Evaluation System (NES) is a computerised battery of tests developed to study the neurological effects of an exposure to environmental agents. The investigators use the digit span test, the continuous performance and the Stroop test.

3. Secondary Endpoints The investigators delineate these outcomes with secondary endpoints to find potential mechanisms of action at the transcript and epigenetic level as with on haematological parameters, markers of inflammation and lipid and protein oxidation products and mitochondrial DNA damage.

3.1. Transcriptomics and Epigenetics The investigators study underlying mechanisms either by full transcriptome analysis and gene specific transcription patterns as well as by specific hypothesis driven microRNA studies. Epigenetic profiles are studied by gene specific methylation sequencing.

3.2. Haematological measurements, markers of inflammation, and oxidative stress.

The investigators measure hemoglobin, red blood cells, fibrinogen, platelets, coagulation factors (II + VII + X), IL-6 and urinary 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxo-dG).

3.3. Mitochondrial DNA damage The investigators measure the mitochondrial DNA content relative to nuclear DNA by means of qPCR, which is a measure of DNA damage and can give an indication of the need to repair mitochondrial DNA damage. As this parameter is an early sensor of DNA-damage these samples will be collected from the whole blood tubes.