Walsh Medical Media

Heading : Results

The mean age of the patients studied was 15.6 ± 0.7 years (range: 12.6-18.2 years). All patients fulfilled the DSM-IV criteria for AN. Amenorrhea was present as primary amenorrhea in seven of the 25 patients (28%) or secondary amenorrhea in 15 of the 25 (60%), and three patients were premenarchal (12%). The mean duration of illness was 20 ± 4 months and the mean duration of amenorrhea was 23 ± 5 months.

Control individuals were 15.5 ± 0.6 years of age (range: 12.9-17.8 years). All patients had a BMI SDS of 0.25 ± 0.11. Two 13.2 and 13.4-years-old girls from the control group were premenarchal and the rest were postmenarchal adolescents and had regular menstrual periods.

Clinical data for patients and controls are summarized in Table 1. There was no significant difference in chronological age (CA) between patients and controls, whereas the BA to CA (BA/CA) ratio was significantly reduced in patients when compared with the controls (patients: 0.28 ± 0.11 years; controls: 1.01 ± 0.04 years; P=0.02); height SDS did not differ between the two groups. Patients had significantly lower BMI (patients: 16.6 ± 0.6 kg/m2; controls: 21.8 ± 0.5 kg/m2; P=0.0001) and BMI SDS (AN: 0.25 ± 0.11; controls: 1.15 ± 0.01, P<0.0001). Fat mass measured by DEXA was reduced to less than 50% in patients compared with the controls (patients: 7.8 ± 0.7 kg; controls: 18.8 ± 0.9 kg; P=0.0001), and percent body fat was significantly reduced in patients (patients: 16.8 ± 1.2; controls: 33.8 ± 1.4; P=0.0002). Lean body mass was also significantly lower in patients (patients: 32.7 ± 1.0 kg; controls: 38.0 ± 1.0 kg; P=0.0001) even after controlling for height and body weight.

Table 1: Comparison of clinical and anthropometric data among patients with anorexia nervosa and controls. (Results are expressed as mean±SD. BMI, Body Mass Index; SDS, Standard Deviation Score. *P<0.05, ***P<0.001.

Bone density data for patients and controls are summarized in Table 2. Lumbar spine (L1–L4) BMD was significantly lower in patients (patients: 0.81±0.04 g/cm2; controls: 0.95±0.03 g/cm2; P=0.02). In 40% of patients with AN, lumbar BMD was more than 1 SDS under the reference healthy mean and 10% of patients had a lumbar BMD of more than 2 SDS under the normal mean.

<div class="table-responsive">
<table class="table table-sm table-bordered">
	<thead>
		<tr>
			<th>Variables</th>
			<th>Patients (n=25)</th>
			<th>Controls (n=30)</th>
			<th>P</th>
		</tr>
	</thead>
	<tbody>
		<tr>
			<td>Lumbar spine BMD (g/cm2)</td>
			<td>0.81±0.04</td>
			<td>0.95 ±0.03</td>
			<td>0.02*</td>
		</tr>
		<tr>
			<td>Lumbar spine BMD z-score</td>
			<td>0.2±0.2</td>
			<td>1.3±0.3</td>
			<td>0.003**</td>
		</tr>
		<tr>
			<td>Lumbar spine BMC (g)</td>
			<td>43±4</td>
			<td>51±3</td>
			<td>0.005**</td>
		</tr>
		<tr>
			<td>Femoral neck BMD (g/cm2)</td>
			<td>0.25±0.01</td>
			<td>0.81±0.02</td>
			<td>0.0001***</td>
		</tr>
		<tr>
			<td>Femoral neck BMD z-score</td>
			<td>0.5±0.4</td>
			<td>1.5±0.1</td>
			<td>0.001**</td>
		</tr>
		<tr>
			<td>Total BMD (g/cm2)</td>
			<td>1.01±0.01</td>
			<td>1.07 ±0.01</td>
			<td>0.58</td>
		</tr>
		<tr>
			<td>TBMC (g)</td>
			<td>1718±42</td>
			<td>1890 ±59</td>
			<td>0.01*</td>
		</tr>
		<tr>
			<td>Fat (kg)</td>
			<td>7.8±0.7</td>
			<td>18.8±0.9</td>
			<td>0.0001***</td>
		</tr>
		<tr>
			<td>Percentage body fat (%)</td>
			<td>16.8±1.2</td>
			<td>33.8±1.4</td>
			<td>0.0002***</td>
		</tr>
		<tr>
			<td>Lean body mass (kg)</td>
			<td>32.7±1.0</td>
			<td>38.0 ±1.0</td>
			<td>0.0001***</td>
		</tr>
	</tbody>
</table>
</div>

Table 2: Comparison of bone density and body composition data among patients with anorexia nervosa and controls. Results are expressed as mean±SD. BMC, Bone Mineral Content; BMD, Bone Mineral Density; TBMC, Total Body Bone Mineral Content. *P<0.05, **P<0.01, ***P<0.001.

The lumbar BMD z-score was significantly reduced in patients with AN (patients: 0.2 ± 0.2; controls: 1.3 ± 0.3; P=0.003). Z-scores were below –1 in 50% and below –2 in 30% of patients. Lumbar BMC was also significantly lower in patients (patients: 43 ± 4 g; controls: 51 ± 3 g; P=0.005).

The reduction in femoral neck BMD was even more severe compared with the reduction in lumbar BMD (patients: 0.25 ± 0.01 g/cm2; controls: 0.81 ± 0.02 g/cm2; P=0.0001), with BMD much lower than 1 SDS in 55% and 2 SDS in 35% of patients. Similar results were obtained after height adjustment, indicating that low BMD was not an artifact. The BMD z-score of femoral neck was also significantly reduced in patients with AN (patients: 0.5 ± 0.4; controls: 1.5 ± 0.1; P=0.001). Z-scores were below –1 in 60% and below –2 in 35% of patients with AN. Total body BMC was significantly lower in patients (patients: 1718 ± 42 g; controls: 1890 ± 59 g; P=0.01), whereas total body BMD did not differ significantly in patients. Differences in femoral neck BMD and total body BMC remained significant after controlling for height.

Serum hormone concentrations, biochemical data, and bone formation marker data are presented in Table 3. The level of serum basal GH was elevated significantly in patients compared with controls (patients: 6.9 ± 2.1 ng/ml; controls: 2.4 ± 1.5 ng/ml; P=0.02). Serum IGF-1 levels were significantly reduced to less than 50% in patients compared with controls (patients: 237 ± 52 ng/ml; controls: 589 ± 46 ng/ml; P=0.0001). In addition, IGF-1 levels in all patients were positively correlated with BMI (r=0.82; P<0.0001), BMI SDS (r=0.94; P<0.0001), percent body fat (r=0.73; P=0.0001), and lean body mass (r=0.79; P=0.001).

Table 3: Comparison of serum hormone concentrations, biochemical data, and bone formation marker among patients with anorexia nervosa and controls. Results are expressed as mean±SD. GH, Growth Hormone; IGF-1, Insulin-Like Growth Factor 1. *P<0.05, **P<0.01, ***P<0.001.

The level of serum ionized calcium was significantly lower in patients (patients: 7.0 ± 0.4; controls: 9.2 ± 0.1; P=0.03), whereas serum phosphorus did not differ among patients and controls. The level of serum 25(OH) D was significantly lower in patients compared with controls (patients: 22 ± 3; controls: 33 ± 1; P=0.04).

Similarly, the level of serum OC was significantly reduced in patients compared with controls (patients: 32.9 ± 6.1; controls: 55.3 ± 5.9; P=0.02). Moreover, there was a strong positive correlation between IGF-1 and OC in patients (r=0.865; P=0.001), whereas that between GH and OC was not significant. In the control group, similar results were found, but the correlations were non-significant (r=0.42; P=0.2). In stepwise regression analysis, IGF-1 led to a 73% (r2=0.75; P=0.001) variation in the levels of OC in patients.

Insulin –like Growth Factor 1 in Adolescent Girls with Anorexia Nervosa: Relation to Bone Formation Parameters

Heading : Results