* !nlaphea.ado version 4.9.0 September 1998     STB-46 sts13
* Aurelio Tobias (IMIM) & Mike Campbell (University of Sheffield)
* Poisson regression allowing for autocorrelation and overdispersion
* (Schwartz et al. J Epidemiol Comminity Health 1996)

program define nlaphea                                           
	version 5.0
	if "`1'" == "?" {                                               
		local i=0
		while `i'<=$N-1 {
		        global S_1 "$S_1 X`i'"
			local i=`i'+1
		}
		local i=1
		while `i'<=$nar {
		        global S_1 "$S_1 R`i'"
			local i=`i'+1
		}
        exit                                                    
        }                                                              

	replace `1'=$X0
	local i=1
	while `i'<=$N-1 {
		replace `1'=`1'+${X`i'}*${VX`i'}
		local i=`i'+1
	}
	local i=1
	while `i'<=$nar {
		replace `1'=`1'+${R`i'}*${RX`i'}
		local i=`i'+1
	}
end