  We constrain the redshift dependence of (rest frame) host galaxy dispersion
measures of localized FRBs by assuming it to vary as a simple power law
($\propto (1+z)^{\alpha}$). We simultaneously fit $\alpha$ as well as the host
dispersion measure to the data of FRBs with known redshifts. We find that
$\alpha\approx 0$ is preferred over higher values of $\alpha$ with either a
positive or negative sign. Such constraints have implications for our
understanding of galaxy formation and can be used to inform galaxy and large
scale simulations.
