But as diet and health improved, children and adolescents have, on average, increased in height by about an inch and a half every 20 years, a pattern known as the secular trend in height.

• 然而随着饮食质量和健康水平的提高，儿童和青少年身高每20年平均增长1.；5英寸，这是身高增长的长期趋势。