Figure 1.

Visual representation of urine collagen type I N-telopeptide (U-NTX) measurement time points and analyses. The menopause transition (MT) was operationalized as the period spanning 2 years before to 2 years after the FMP. In all participants, U-NTX was measured at 2 time points: (1) once around the start of the MT, indicated by #1; and (2) once at the first visit after the MT (early postmenopause), shown as #2. In most women, the first U-NTX measurement was from their last visit before the MT. Some women entered the study after the MT had started; the first U-NTX measurement in these women was their SWAN baseline visit. The rate of increase in U-NTX over the MT was calculated differently in these 2 groups and is detailed in the text. In our first analysis, we examined whether rate of increase in U-NTX over the MT was associated with incident fracture after early postmenopause. In our second analysis, we assessed whether greater U-NTX in early postmenopause was associated with subsequent fracture.