A health official says figures from Arkadelphia, the first school district to finish measuring the body mass of all its students, are cause for alarm. The figures say nearly two-fifths of the districts two-thousand, 51 students are either at risk of becoming overweight or are overweight already. Numbers from Arkadelphia`s five schools show that boys are more likely to be overweight than girls, and that certain grades are heavier than others. Doctor Joe Thompson, project director for the Arkansas Center for Health Improvement, said the results in Arkadelphia are a major cause for concern. Thompson said the state has a major problem with child and adolescent obesity. The numbers were gathered under a new law. The law requires public schools to work up an annual body mass index, using height, weight and age, to indicate body mass of each student. It also rids school cafeterias of vending machines and creates the Arkansas Child Health Advisory Committee. The numbers are the first in a program that aims to screen all 450,000 Arkansas public school students.