The best model for the establishment of the NGF population after conception, and the subsequent decline until 25 years of age is described by an ADC model with parameters

= 5.79 (95% CI 5.03–6.55),

= 28.0 (95% CI 15.8–40.2),

= 57.4 (95% CI 33.1–81.8),

= 0.074 (95% CI 0.067–0.081), and

= 34.3 (95% CI −4.2–72.8). This model has correlation coefficient

= 0.95, fit standard error = 0.29 and F-value = 585. This figure shows the dataset (n = 126), the model, the 95% prediction limits of the model, and the 95% confidence interval for the model. The horizontal axis denotes age in months up to birth at age zero, and age in years from birth to 25 years.