"Secondary hyperparathyroidism and renal osteodystrophy are major problems in patients with end-stage renal failure and may result in poor growth in children on dialysis. Whether vitamin D sterols should be given intermittently or daily remains a controversial issue. We studied 16 bilaterally nephrectomised infants with congenital nephrosis of the Finnish type (median age 0.54 years), all on peritoneal dialysis. Nine of them were receiving intermittent 1-alpha calcidol therapy and seven daily 1-alpha calcidol therapy. The target serum parathyroid hormone (PTH) level was 2-3 times the upper limit of normal (ULN). There were no statistically significant differences in PTH values between the groups (1.7-times vs 0.5-times the ULN at 3 months and 3.1-times vs 3.4-times the ULN at 6 months, respectively). The required weekly doses of 1-alpha calcidol were low, and there were no significant differences between the intermittent and daily groups (0.06 mu g/kg vs 0.04 mu g/kg at 3 months and 0.09 mu g/kg vs 0.05 mu g/kg at 6 months, respectively). The infants on intermittent 1-alpha calcidol showed significant catch-up growth during dialysis after nephrectomy relative to the infants on daily 1-alpha calcidol (-1.6 SD to -0.7 SD vs -1.4 SD to -1.0 SD, respectively; P < 0.05). Our results indicate that either intermittent or daily vitamin D analogue therapy, if started early, will prevent secondary hyperparathyroidism equally well in children on peritoneal dialysis (PD), but intermittent therapy might be more favourable for growth."