Polar stays expose people to extreme climate, isolation and confinement. The combination of these factors induces psychological disorders, sleep disorders, immune and endocrine disturbances, and deficiencies. In the TAAF, (French Southern and Antarctic Lands) two types of population coexist: winter residents, exposed to these stressors over long periods, and country people, who benefit from milder conditions and only make short stays. In this context, the investigators have decided to set up this cohort study with the objective of comparing the state of health of the winterers of the TAAF from 2012 to 2017 with that of the country people of the same period, before their stay, during and the year following their return.

Participants will answer to a questionnaire. This questionnaire will determinate participants health about following areas : psychological disorders, sleep disorders, immune and endocrine disturbances, and any deficiencies.

Inclusion Criteria:

for the exposed group are:

• To have carried out one or more wintering in one of the districts of the TAAF, that means a stay of at least six consecutive months including winter;
• Have started their first wintering between 01jan2012 and 31dec2017;
• Know how to read and write French.

for the non-exposed group are:

• To have taken part in one or more summer campaigns between 01jan2012 and 31dec2017;
• Never have overwintered;
• Not having been refused wintering for health reasons or following psychological tests;
• Knowing how to read and write French.

Exclusion Criteria:

• Persons under guardianship or guardianship, deceased persons, persons refusing to participate in the study