No compensation shall be payable for an occupational disease if the employee, at the time of entering into the employment of the employer by whom the compensation would otherwise be payable, or thereafter, willfully and falsely represents in writing that he or she has not previously had the disease that is the cause of the disability or death. Where an occupational disease is aggravated by any other disease or infirmity, not itself compensable, or where disability or death from any other cause, not itself compensable, is aggravated, prolonged, accelerated, or in any way contributed to by an occupational disease, the compensation payable shall be the proportion only of the compensation that would be payable if the occupational disease were the sole cause of the disability or death as that occupational disease, as a causative factor, bears to all the causes of that disability or death, the reduction in compensation to be effected by reducing the number of weekly payments or the amounts of the payments, as under the circumstances of the particular case may be for the best interests of the claimant or claimants.