Menopause and skin: new study reveals hidden links

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: 1. Participants must possess basic Chinese literacy skills (reading comprehension and expression) to complete questionnaires independently. 2. Voluntary participation and signed informed consent. 3. Willingness to comply with all study requirements and assessments. 4. Early Perimenopausal Group： 1. Healthy women aged 45-50 (±3) years. 2. STRAW Stage -2 / Early Perimenopause: Experiencing a persistent change in menstrual cycle length of \>7 days from their normal cycle, but with no occurrence of 60 or more days of amenorrhea (i.e., still having menstrual periods). 5. Late Perimenopausal Group： 1. Healthy women aged 50-55 (±3) years. 2. STRAW Stage -1 / Late Perimenopause: Experiencing ≥2 consecutive cycles with a length of ≥60 days, or the presence of ≥60 days of amenorrhea. 6\) Postmenopausal Group： <!-- --> 1. Healthy women aged 55-60 (±3) years. 2. STRAW Stage +1 / Postmenopause: Last menstrual period occurred at least 12 months prior. 7）Young Control Group： 1. Healthy women aged 18-25 (±3) years. 2. Biological daughters of participants in either the Late Perimenopausal Group or the Postmenopausal Group. 3. Regular menstrual cycle, with a cycle length ranging between 25-35 days. Exclusion Criteria 1. Presence of open wounds, clearly visible scars, acne marks, or other significant skin imperfections at the measurement sites. 2. History of skin diseases affecting the evaluation of the study areas (e.g., psoriasis, atopic dermatitis, skin cancer). 3. Women who are currently pregnant or breastfeeding. 4. Use of systemic estrogen or progesterone hormone replacement therapy within the past 6 months. 5. Presence of acute or severe chronic diseases currently under treatment. 6. Any known condition that significantly impairs cognitive or behavioral abilities. 7. Considered by the investigator or qualified professional to have other medical or specific reasons that may interfere with the evaluation of study results. 8. Early Perimenopausal Group \& Late Perimenopausal Group \& Postmenopausal Group: a) Current use of systemic hormone replacement therapy (HRT). b) Topical application of anti-aging products (e.g., retinoids, alpha/beta hydroxy acids) on the measurement areas within the past 3 months. c) History of breast cancer or oophorectomy. 9） Young Control Group: 1. Currently planning for pregnancy, pregnant, or lactating. 2. Diagnosis of Polycystic Ovary Syndrome (PCOS).