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ashkin, Simmons, Shwill, rt o7., Marii`and Annual Change in FEV, - O ° TABLE 1 OEMOGRAINIC AND SMOKING CNAIIAMKD-nC3 Or SUBJECTS AT VISrr 1 N Mean ,lye Tob4Or9 mariiYana KVI 3uolects (W) V) (evorm4V4) u -M (141+11/.31 C01,101- (%,+M Ms 101130 31.5to.s• 0-0200 3.410.6 4.1 it0.6 Mrs 61131 13.630.5 16.4*1.31 16.011.31 36.2611.9 108*1,4 3.630.3 TS 33/32 36.7*0.94 27.111.7 21A 11.9 0.010.0 43.1139 OA 10.0 10611.1 NS 53/33 32.0a0.6 0.1*00 0.010.0 0.040.0 0.020.0 106*1.9 10911,41 Definition d *bb1^4&tioiv. M o nyle r+remeN; Ms a n,, n usn, smoke MT3 + man)uana pun tobavo vnoken; TS+,Ob4crn •ar�c NS • norunwiew jamas/d a number d nsCo,n' t IWraeQuiVelMU) per � iW"'Yr v nYmbe, d sm,k. )OVIb Co, Eay a nYmMr d Jean unoked. lomLeq,ry Itnu) per SLM. 37 S 1 Signi6carey bvwr then T3 (p < 11.01). _ 1 slgvfw try NOMr Von Wier 0n&* ra6 WWW (p < 0.05). marijuana, reduced their daily amount of marijuana use, others (31% of MS and 2617, of MIS) Increased their use•, the resultant average reduction In use was relatively small (0.7 and 1 joint among MS and MTS, respectively). Among initial tobacco smok- ers, including those who subsequently quit smoking tobacco, 49% of IS and 36% or MTS reduced their daily number of cigarettes, whereas 190/6 of TS and 34176 of MTS increased their dally use of tobacco; the mean changes in IS and MTS were reductions of 4.8 end 0.8 cigarettes/d, respectively. Figure I shows the estimated decline in FEV, with age by smoking status derived from the random -effects model for men (Figure IA) and women (Figure III), with smoking status for tobacco and marijuana, and the lobaceo-marijuana interaction entered as a tinwdependent covariable. In men, tobacco smok- ing, but not marijuana smoking, was associatod with a signifi- cantly steeper decline in FEV, compared with nonsmoking, in- dicating an accelerated decline In lung function with increasing age for tobacco smoking but not for marijuana smoking com- pared with nonsmoking. Similar findings were observer! In women, although the slope difference for tobacco did not achieve statisti- cal Lign)ficance. A negative interaction was found between mariju- ana and tobacco smoking in men but not in women (Figure )A; Table 4). When the Intensity of marijuana smoking on FEV. decline with age was examined in men, no differences were noted be- tween even quite heavy marijuana smoking (14:, 3 joints/d) and nonsmoking of marijuana (Figure 2A). Similar findings were noted in women. In contrast, the amount of tobacco smoked was significantly correlated with decline In FEV, with age (Figure 2E), although a dose -response relationship for tobacco was not demonstrated in women. Figure 3 shows the effect of the continuity of marijuana smoking among men who were nonsmokers of tobacco (Figure 3A) or continuing tobacco smokers (Figure 3$), with marijuana smoking status (never, continuing, intermittent) as a constant covariable. Neither the continuing nor the intermittent mariju- ana smokers exhibited any significantly different rates ordecline in FEV, as compared with neva smokers ormarijuana. This lack TABLE 2 NUMBER OF SUBJECTS WrTH ONE OR MORE ygn-S Visit No. 1 k 3 4 s 6 1 Tdd Mak TB 49 36 23 2) 21 14 266 Female 41 24 11 16 IS 9 6 126 TOW_ 139 73 ss 41 $6 30 A 394 143 of a marijuana effect "a independent or the effect of tobacco, as indicated by the similarity of the findings for the different categories of marijuana smokers (never, continuing, later mit- tent) when the analyses were confined to tither never tobacco smokers (Figure 3A) or condnuing tobacco smokers (Figure 38). Similar observations were noted in women. The slopes for all categorles of marijuana smokers are steeper among the contin- uing tobacco smokers than among the never tobacco smokers, As a consequence of the effect of tobacco (not marijuana) on the rate of decline in FEV,. In contrast to marijuana, the continuity of tobacco smoking did affect the rate of decline in lung function, with a consistent gradient of increasing decline from never through intermittent to continuing tobacco smoking, as shown for men in Figure 4. Table 4 shows the results of random -effects models, which are plotted in Figures 1 through 4;1 tests were used to determine whether the slope coefficients differed from zero, The listed coefficients represent the decline in FEV, with age for each of the rererc= groups, and for the nonrefefenee groups they rep- resent the rate of decline relative to each reference group. For oiample, the results for Figure ]A Indicate that the reference group (nonsmokers) had a 253 ml/yr tate of decline, whereas Mari. Juana smokers had a 30.8 ml/yr rate of decline, or a difference of 5.5 ml/yr (as shown in Table 4) from the reference group. MTS had a decline 10.5 ml/yr greater than did NS, which Is the sum of the marijuana and tobacco terms and their interaction (which is zero for all groups except MTS). Slight differences from the figures arc due to round -off error. According to the model for Figure 2A, FEV, in marijuana smokers declined only 0.036 ml/yr faster than in nonsmoker of marijuana for each joint per day regularly smoked. In Figure 3A (never smokers or tobacco only), FEV, in intermittent and continuing smokers of marijuana de- clined 0.97 and 194 ml/yr faster than in never smokers of mari- juana, respectively. TABLE 3 CONFINUrrY OF SMOKING STATUS Nymber of Subjects in Fxh Category lmdal Marquarsa Tobacco --- W Status n Cm4nuing thfil nNMt Continuing Intermittent MS 67 71 16 MIS63 Ts — 17 40 6 23 NS63 42 37 S _ 2