Table 3.
Comparison of possible risk factors between patients with low BMD (Z‐score <−2) and patients with BMD within normal range (Z‐score >−2)
| Continuous data | Low BMD | Normal BMD | P (Mann‐Whitney U test) | |||
|---|---|---|---|---|---|---|
| N | Median | N | Median | |||
| Age most recent DXA (year) | 10 | 27.5 | 171 | 28.0 | .864 | |
| Recent BMI | 10 | 21.7 | 167 | 24.9 | .053 | |
| Mean Phe the year before the recent DXA (μmol/L) | 10 | 800 | 156 | 775 | .573 | |
| Categorical data | Low BMD N (%) | Normal BMD N (%) | P (Fisher's Exact test) | |||
| Gender M | 8 (80) | 68 (40) | .018 * | |||
| Sapropterin dichloride use yes | 1 (11) | 22 (14) | >.99 | |||
| Low vitamin D concentration yes | 5 (50) | 50 (31) | .294 | |||
| Vitamin D supplementation yes | 3 (38) | 39 (26) | .434 | |||
| Calcium supplementation yes | 3 (38) | 27 (18) | .174 | |||
| (ex) Smoker status yes | 0 | 23 (23) | .574 | |||
| Alcohol consumption (on average >2 units/day) yes | 2 (50) | 25 (25) | .272 | |||
| Natural protein intake | Missing or not adherent to a diet | 3 (30) | 27 (16) | .588 | ||
| Severe protein restriction (<10 g/day) | 1 (10) | 42 (25) | ||||
| Moderate protein restriction (>10 to 20 g/day) | 1 (10) | 35 (21) | ||||
| Mild protein restriction (>20 to 40 g/day) | 2 (20) | 28 (16) | ||||
| protein intake > recommended intake (>40 g/day)a | 3 (30) | 39 (23) | ||||
Abbreviations: BMD, bone mineral density; BMI, body mass index; DXA, dual‐energy X‐ray absorptiometry.
a
An amount of >40 g was based on the safe amount of protein of 0.8 g/kg/day according to FAO/WHO/UNU with some patients weighing around 50 kg.
*
Not significant (P > .05) after post‐hoc adjustment of P value by Bonferroni method (multiplying P value by the number of tests (11)).