  We report results of a re-analysis of archival Spitzer IRAC direct imaging
surveys encompassing a variety of nearby stars. Our sample is generated from
the combined observations of 73 young stars (median age, distance, spectral
type = 85 Myr, 23.3 pc, G5) and 48 known exoplanet host stars with
unconstrained ages (median distance, spectral type = 22.6 pc, G5). While the
small size of Spitzer provides a lower resolution than 8m-class AO-assisted
ground based telescopes, which have been used for constraining the frequency of
0.5 - 13 $M_J$ planets at separations of $10 - 10^2$ AU, its exquisite infrared
sensitivity provides the ability to place unmatched constraints on the
planetary populations at wider separations. Here we apply sophisticated
high-contrast techniques to our sample in order to remove the stellar PSF and
open up sensitivity to planetary mass companions down to 5\arcsec\ separations.
This enables sensitivity to 0.5 - 13 $M_J$ planets at physical separations on
the order of $10^2 - 10^3$ AU , allowing us to probe a parameter space which
has not previously been systematically explored to any similar degree of
sensitivity. Based on a colour and proper motion analysis we do not record any
planetary detections. Exploiting this enhanced survey sensitivity, employing
Monte Carlo simulations with a Bayesian approach, and assuming a mass
distribution of $dn/dm \propto m^{-1.31}$, we constrain (at 95% confidence) a
population of 0.5 - 13 $M_J$ planets at separations of 100 - 1000 AU with an
upper frequency limit of 9%.
