Table 3.
Dose–response associations between different routes of opium use and the risk of developing different cancers
| Never used this route | First quartile | Second quartile | Third quartile | Fourth quartile | Ptrend | |
|---|---|---|---|---|---|---|
| All cancers combined (n=1833) | ||||||
| Any route (n=482) | 1 (ref) | 1·24 (1·01–1·53) | 1·22 (0·99–1·51) | 1·43 (1·18–1·75) | 1·70 (1·42–2·04) | <0·0001 |
| Smoking (n=322) | 1 (ref) | 1·12 (0·88–1·43) | 1·00 (0·77–1·30) | 1·33 (1·07–1·67) | 1·64 (1·33–2·02) | <0·0001 |
| Ingestion (n=201) | 1 (ref) | 1·20 (0·88–1·64) | 1·53 (1·16–2·02) | 1·41 (1·05–1·91) | 1·49 (1·14–1·95) | <0·0001 |
| Gastrointestinal cancers combined (n=914) | ||||||
| Any route (n=242) | 1 (ref) | 1·28 (0·96–1·70) | 1·19 (0·89–1·60) | 1·28 (0·97–1·70) | 1·48 (1·14–1·91) | 0·0007 |
| Smoking (n=162) | 1 (ref) | 1·32 (0·96–1·81) | 0·99 (0·68–1·42) | 1·22 (0·89–1·69) | 1·44 (1·06–1·95) | 0·014 |
| Ingestion (n=99) | 1 (ref) | 1·07 (0·68–1·68) | 1·35 (0·90–2·00) | 1·33 (0·88–2·01) | 1·30 (0·88–1·90) | 0·033 |
| Respiratory cancers combined (n=154) | ||||||
| Any route (n=80) | 1 (ref) | 1·14 (0·54–2·40) | 2·38 (1·37–4·11) | 2·26 (1·30–3·92) | 3·22 (2·02–5·14) | <0·0001 |
| Smoking (n=53) | 1 (ref) | 0·29 (0·07–1·20) | 1·42 (0·73–2·76) | 1·76 (0·98–3·14) | 2·83 (1·77–4·52) | 0·0001 |
| Ingestion (n=36) | 1 (ref) | 2·16 (1·04–4·48) | 2·63 (1·39–4·97) | 1·19 (0·48–2·96) | 1·94 (1·03–3·68) | 0·0081 |
| Oesophageal cancer (n=342) | ||||||
| Any route (n=93) | 1 (ref) | 1·34 (0·84–2·12) | 1·18 (0·73–1·91) | 1·42 (0·90–2·21) | 1·60 (1·06–2·42) | 0·0099 |
| Smoking (n=65) | 1 (ref) | 1·34 (0·78–2·31) | 1·00 (0·54–1·85) | 1·62 (1·00–2·61) | 1·79 (1·12–2·86) | 0·0046 |
| Ingestion (n=37) | 1 (ref) | 1·34 (0·71–2·54) | 1·05 (0·51–2·14) | 1·53 (0·83–2·84) | 0·91 (0·44–1·87) | 0·527 |
| Gastric cancer (n=308) | ||||||
| Any route (n=90) | 1 (ref) | 1·33 (0·83–2·13) | 1·57 (1·01–2·43) | 1·19 (0·73–1·94) | 1·37 (0·88–2·11) | 0·067 |
| Smoking (n=62) | 1 (ref) | 1·53 (0·93–2·53) | 1·63 (1·00–2·66) | 0·93 (0·50–1·72) | 1·27 (0·75–2·16) | 0·215 |
| Ingestion (n=34) | 1 (ref) | 0·75 (0·30–1·83) | 1·42 (0·74–2·70) | 1·33 (0·67–2·62) | 1·16 (0·60–2·23) | 0·320 |
| Lung cancer (n=116) | ||||||
| Any route (n=57) | 1 (ref) | 1·15 (0·49–2·73) | 2·34 (1·23–4·43) | 2·04 (1·05–3·95) | 3·19 (1·85–5·50) | <0·0001 |
| Smoking (n=37) | 1 (ref) | 0·40 (0·09–1·64) | 1·16 (0·50–2·72) | 1·71 (0·86–3·38) | 2·73 (1·57–4·75) | 0·0006 |
| Ingestion (n=27) | 1 (ref) | 2·70 (1·23–5·93) | 2·74 (1·30–5·79) | 1·35 (0·48–3·74) | 1·85 (0·85–4·02) | 0·024 |
| Colon cancer (n=95) | ||||||
| Any route (n=15) | 1 (ref) | 1·58 (0·71–3·51) | 0·49 (0·11–2·06) | 0·74 (0·22–2·44) | 0·66 (0·19–2·25) | 0·379 |
| Smoking (n=10) | 1 (ref) | 1·75 (0·75–4·11) | .. | 0·92 (0·28–3·00) | 0·33 (0·04–2·47) | 0·226 |
| Ingestion (n=5) | 1 (ref) | 0·73 (0·10–5·31) | 1·49 (0·35–6·18) | .. | 1·47 (0·34–6·27) | 0·994 |
| Brain cancer (n=80) | ||||||
| Any route (n=17) | 1 (ref) | 0·28 (0·03–2·05) | 2·08 (0·95–4·58) | 0·83 (0·25–2·76) | 1·33 (0·48–3·63) | 0·476 |
| Smoking (n=8) | 1 (ref) | 0·32 (0·04–2·37) | 0·95 (0·29–3·11) | 0·59 (0·14–2·49) | 0·68 (0·16–2·94) | 0·383 |
| Ingestion (n=10) | 1 (ref) | .. | 3·88 (1·51–9·94) | 1·89 (0·45–7·97) | 2·70 (0·79–9·20) | 0·017 |
| Pancreatic cancer (n=78) | ||||||
| Any route (n=22) | 1 (ref) | 0·91 (0·28–2·97) | 1·50 (0·58–3·90) | 1·19 (0·41–3·43) | 2·66 (1·23–5·74) | 0·028 |
| Smoking (n=16) | 1 (ref) | 0·80 (0·19–3·31) | 1·25 (0·38–4·10) | 1·52 (0·53–4·31) | 2·82 (1·21–6·60) | 0·028 |
| Ingestion (n=8) | 1 (ref) | 0·64 (0·08–4·69) | 1·87 (0·57–6·13) | .. | 2·36 (0·81–6·87) | 0·347 |
| Liver cancer (n=73) | ||||||
| Any route (n=20) | 1 (ref) | 1·08 (0·38–3·04) | 0·76 (0·23–2·53) | 1·25 (0·48–3·27) | 1·76 (0·77–4·01) | 0·254 |
| Smoking (n=8) | 1 (ref) | 0·61 (0·14–2·53) | .. | 0·81 (0·25–2·65) | 0·84 (0·25–2·79) | 0·340 |
| Ingestion (n=12) | 1 (ref) | 2·29 (0·70–7·44) | 1·37 (0·32–5·75) | 1·54 (0·36–6·50) | 3·37 (1·27–8·92) | 0·018 |
| Bladder cancer (n=47) | ||||||
| Any route (n=23) | 1 (ref) | 3·24 (1·28–8·20) | 0·55 (0·07–4·21) | 3·31 (1·27–8·59) | 4·28 (1·81–10·15) | 0·0009 |
| Smoking (n=14) | 1 (ref) | 2·61 (0·99–6·87) | .. | 1·53 (0·45–5·16) | 2·62 (1·01–6·80) | 0·107 |
| Ingestion (n=10) | 1 (ref) | 1·05 (0·14–7·84) | 2·83 (0·84–9·52) | 2·05 (0·47–8·84) | 3·12 (1·01–9·60) | 0·018 |
| Laryngeal cancer (n=38) | ||||||
| Any route (n=23) | 1 (ref) | 1·11 (0·24–5·01) | 2·55 (0·87–7·42) | 2·98 (1·08–8·22) | 3·34 (1·33–8·34) | 0·0004 |
| Smoking (n=16) | 1 (ref) | .. | 2·19 (0·73–6·55) | 1·99 (0·66–6·01) | 3·15 (1·30–7·58) | 0·0006 |
| Ingestion (n=9) | 1 (ref) | 0·87 (0·11–6·52) | 2·31 (0·68–7·79) | 0·79 (0·10–5·94) | 2·08 (0·68–6·38) | 0·206 |
Data are adjusted hazard ratio (95% CI), unless otherwise indicated. This model used age as the timescale and was adjusted for sex (male vs female), ethnicity (Turkman vs non-Turkman), residence (urban vs rural), wealth score quartiles, smoking cigarettes (ever vs never), cumulative pack-years of smoked cigarettes (continuous variable), and regular alcohol drinking (never vs ever). For participants who used opium via both routes, we calculated the amount of opium used through each route separately; therefore, the numbers in each category of smoking and ingestion routes do not sum to the number of any route because these categories also include the few dual-route opium users. The amount of opium was calculated as nokhod-years. In each quartile, the cumulative opium used through the presented routes was as follows: any route, first quartile (≤5), second quartile (5·1–21), third quartile (21·1–60), and fourth quartile (>60); opium smoking, first quartile (≤4), second quartile (4·1–18), third quartile (18·1–60), and fourth quartile (>60); and opium ingestion, first quartile (≤9), second quartile (9·1–30), third quartile (30·1–78), and fourth quartile (>78).