OBJECTIVE Age at menarche (AAM) is an important indicator of physiological development in women, and delayed AAM has been associated with chronic illnesses. We investigated predictive factors at diagnosis that influence AAM in adolescents with chronic respiratory diseases. STUDY DESIGN AAM was assessed in 1207 northern Italian female aged 11-24 (1062 healthy, 98 with asthma and 47 with cystic fibrosis [CF]). AAM was defined by recall and status quo methods. We studied anthropometric data, metabolic status, diagnosis parameters, presence of irregular menses. Clinical data of subjects with chronic respiratory illness were compared with that of healthy adolescents. RESULTS Mean AAM for healthy adolescents was 12.49 ± 1.2 years. Mother's AAM was positively associated with that of their daughters (P
