LOS ANGELES — Among the concerns surrounding the rollout of President Barack Obama’s health care overhaul was that too few young, healthy people would sign up — a problem that could undermine the financial viability of the federal law.

The insurance industry has increasing cause for concern as early enrollment reports suggest a trend that could cause insurance premiums and deductibles to rise sharply. Along with the paltry enrollment numbers released this week, officials in a handful of states said those who had managed to sign up were generally older people with medical problems.

Insurers have warned that they need a wide range of people signing up for coverage because premiums paid by adults in the younger and healthier group, between 18 and 35, are needed to offset the cost of carrying older and sicker customers who typically generate far more in medical bills than they contribute in premiums.

The first set of enrollment data revealed that 106,000 people signed up for coverage nationwide, far short of the 500,000 initial sign-ups the Obama administration had expected. In states where officials discussed more detailed information, it also became apparent that the people who flocked to the exchanges after they opened Oct. 1 were those who were desperate for coverage.