Epidemiology of Short Stature

Frequency:

In the US: In 1994, Lindsay et al studied 114,881 school children in Utah. After 1 year, 79,495 of the original group were available for evaluation. Of these, 555 (0.7%) had heights that were below the third percentile and a growth rate that was fewer than 5 cm/y. When examined further, causes for short stature within this group of children included familial short stature (37%), constitutional delay (27%), a combination of familial short stature and constitutional delay (17%), other medical causes (10%), idiopathic short stature (5%), GH deficiency (3%), Turner syndrome (3% of girls), and hypothyroidism (0.5%).

Internationally:

General
Several studies have been conducted to determine the frequency of various causes of short stature. In 1974, Lacey and Parkin evaluated children in Newcastle upon Tyne in England. They studied 2256 children, of whom 111 were below the third percentile in stature. Of the 98 children that they were able to examine, only 16 had evidence of organic disease causing their short stature. Diagnoses included Down syndrome, cystic fibrosis, chronic renal insufficiency, GH deficiency, juvenile rheumatoid arthritis (treated with glucocorticoid), and Hurler syndrome.

Short stature due to growth hormone deficiency (GHD)
Frequency of isolated GHD has been reported to range from 1 case per 1,800 children in Sri Lanka (a probable overestimate due to liberal diagnostic criteria) to 1 case per 30,000 children in Newcastle, UK (a probable underestimate due to its reliance on referral rates to a growth clinic).

Mortality/Morbidity:

General
Short stature has been shown to have far-reaching effects on psychological well-being, including poor academic achievement (despite normal intelligence, healthy family dynamics, and high socioeconomic status) and behavioral problems (eg, anxiety, attention-seeking actions, poor social skills). Morbidity related to the underlying cause of the growth failure may also be present.

Mortality rates in children with growth failure relate to the underlying cause of the growth failure. Mortality is not related to growth failure itself; rather, it is related only to the cause of the growth failure.

Short stature due to growth hormone deficiency (GHD)
Mortality in children with GHD is due almost entirely to other pituitary hormone deficiencies. These children have an increased relative risk of death in adulthood from cardiovascular causes resulting from altered body composition and dyslipidemia.

Most morbidity in children with GHD relates to short stature. Average adult height for untreated patients with severe isolated GHD is 143 cm in men and 130 cm in women. Approximately 5% of children with GHD also have episodes of hypoglycemia, particularly in infancy, which resolve with GH therapy.

Adults with untreated GHD have altered body composition (eg, excess body fat, lower lean body mass), decreased bone mineralization, cardiovascular risk factors (in particular, altered blood lipids), and decreased exercise tolerance. In addition, these patients may be socially isolated.

Sex: The sex distribution of patients with idiopathic GHD in the National Cooperative Growth Study is 73% male and 27% female. Among patients with organic GHD, in which no sex difference should be present, the ratio is 62% male to 38% female.

Age: Although most cases of idiopathic GHD are thought present at birth, diagnosis often is delayed until concern is raised about short stature. Diagnosis of GHD is made during 2 broad age peaks. The first age peak occurs at 5 years, a time when children begin school and the height of short children probably is compared to that of their peers. The second age peak occurs in girls aged 10-13 years and boys aged 12-16 years. This second peak possibly relates to the delay in puberty associated with GHD. Children with GHD may seem to grow at a slower rate than their peers, because their peers are in the midst of the pubertal growth spurt, while children with GHD have not yet entered this phase.

Contributed by Lawrence Oh

Reference:
http://www.emedicine.com/ped/topic1810.htm
http://www.emedicine.com/ped/topic902.htm