Green Tobacco Sickness and Salivary Cotinine Levels

in Connecticut Shade Tobacco Farmworkers

Marcia Trapé-Cardoso, MD*; Anne Bracker, CIH, MPH;

Michael Grey, MD, MPH; Eddie Sapiain, CTCOSH; Cheryl

Oncken, MD; Laura Victoria Barrera, MPH; Bruce Gould, MD University of CT Health Center and School of Medicine

131st Annual APHA Meeting – November 17, 2003

AbstractBackground: Green Tobacco Sickness (GTS), acute nicotine poisoning,

has been reported among workers who harvest tobacco. The objective of this prospective study was to determine whether or not the Connecticut shade tobacco farmworkers who have symptoms consistent with GTS also have a corresponding increase in salivary cotinine.

Methods: The study utilized a prospective cohort design to evaluate salivary cotinine concentrations and symptoms of possible GTS in a population of shade tobacco farmworkers compared to a control group of nursery workers. Workers were assessed at two points in time (planting and harvest season). An additional group of exposed workers were recruited during harvest and added to a cross-sectional. A Repeated Measures Analyses of Covariance (ANCOVA) statistical model was used to analyze the data.

Results: There was no statistically significant increase in salivary cotinine over time in this population of shade tobacco farmworkers. During the harvest season there was not a significant difference between the cotinine levels of the tobacco and the nursery workers when the data was controlled for tobacco use. During the harvest season, 4 tobacco workers (8%) and 1 nursery worker (2%) reported symptoms consistent with GTS. Because the 4 tobacco workers were recruited during the cross-sectional phase of the study, they did not have baseline cotinine levels.

Conclusion: Control strategies, specifically the careful techniques used to handle shade tobacco leaves, appear to reduce shade tobacco farmworkers’ dermal nicotine absorption. Limitations of this study and need for further studies are discussed.

Green Tobacco Sickness

• Acute nicotine poisoning presumably from the transdermal absorption of nicotine from tobacco leaves.

• Case definition:Headache or Dizziness and Nausea or Vomiting after working in tobacco (Arcury, 2001)

• Prevalence estimates: 9-41% (Weizenecker, 1970, Gehlbach, 1974, Behlbach, 1975, Ballard, 1995, Quandt, 2000 and Arcury, 2001)

Cotinine: a biomarker of exposure• GTS non-specific constellation of symptoms• Cotinine (metabolite of nicotine with ½ life

of 20 hours): a biological marker of exposure• Salivary Cotinine correlates well with serum

cotinine• Specimens are easily collected by non-

invasive procedure

Do CT Tobacco Farmworkers Report Green Tobacco Sickness?• No cases diagnosed among migrant shade tobacco

farm workers seeking care at outreach clinics• Retrospective Review of shade tobacco workers

seeking care at a medical clinic (2001) found:– ICD-9 codes – 15 %- primary or secondary

diagnosis that could be categorized as possible GTS (no ICD-9 code for GTS)

– Chart review for tighter case definition (all nonsmokers) – 4 %

• Trapé et al, JOEM 6/2003

Seeds planted in rowsUnder shade

Stringing

Wrapping and Suckering

Harvesting with Bicycle Powered Conveyor

Methods• Prospective Cohort• Shade tobacco workers (exposed) and Nursery

workers (non exposed)• Planting Season (Time 1) and Harvest Season (Time

2) – Questionnaire Interview – Biological Monitoring (salivary cotinine) and– CO in exhaled breath

• Statistical analysis– Repeated Measures Analyses of Covariance (ANCOVA)

Results

Shade tobacco Workers (exposed)Time 1- 53 Planting SeasonTime 2- 29 (55%) Harvest Season

+24 (added tobacco workers for a cross- sectional survey because many workers left before time 2)

Nursery Workers (non exposed)Time 1- 59 Planting SeasonTime 2- 43 (73%) Harvest Season

Results- Demographic DataShade Tobacco (Exposed) and Nursery Workers (Unexposed)

Shade Tobacco

n=77 (%)

Nursery

n=59 (%)

P-value

Any tobacco use (self report) 41 (53.2%) 26 (44.1%) 0.757

CO exhaled breath > 8 15 (19.5%) 13 (22%) 0.715

Any second hand smoke- time 1

time 2

53 (100%)

50 (94.3%)

21 (35.6%)

17 (38.6%)

0.000

0.000

Living in Company Housing 77 (100%) 0 (0.0%) 0.000

Country of Origin

US

Mexico

PR

Honduras

Jamaica

Other

2 (2.6%)

26 (33.8%)

37 (48.1%)

1 (1.3%)

7 (9.1%)

4 (5.1%)

3 (5.1%)

6 (10.2%)

25 (42.4%)

0 (0.0%)

1 (1.7%)

24 (40.6%)

0.000

Female 0 (0%) 14 (23.7%) 0.000

Results- Demographic DataShade Tobacco (Exposed) and Nursery Workers (Unexposed)

Shade Tobacco

n=77 (SD)

Nursery

n=59 (SD)

P-value

Mean Age 43.6 (12.2) 33.0 (13.3) 0.000

Mean Height (in meters) 1.7 (0.10) 1.6 (0.12) 0.000

Mean Weight (in kilograms) 80.0 (12.4) 67.8 (13.5) 0.000

Body Mass Index 26.7 (3.8) 26.2 (5.4) 0.177

Salivary Cotinine (ng/dL) in Paired Workers Type of Farm Sample size (n) Planting Season (Time 1)

Mean (SD)

Harvest Season (Time 2)

Mean (SD)

P value

Tobacco Workers All (n=29) 101.0 (119.2) 84.9 (107.1) 0.586

Tobacco Use

+ Self Report (n=19)

137.9 (114.7) 124.3 (113.0) 0.570

Tobacco Use

CO > 8 (n=11)

201.6 (98.3) 179.2 (110.7) 0.508

No Tobacco Use

- Self Report (n=10)

30.9 (97.7) 10.2 (26.3) 1.000

No Tobacco Use

CO < 8 (n=18)

39.6 (84.7) 27.3 (49.4) 1.000

Nursery Workers All (n=43) 71.7 (107.3) 98.5 (136.4) 0.002

Tobacco Use

+ Self Report (n=29)

21.5 (50.4) 26.7 (61.4) 0.276

Tobacco Use

CO > 8 (n=23)

124.2 (122.1) 157.6 (143.3) 0.004

No Tobacco Use

- Self Report (n=14)

173.8 (121.8) 247.1 (129.3) 0.003

No Tobacco Use

CO < 8 (n=20)

10.0 (28.8) 30.5 (90.8) 0.138

ANCOVA: Salivary Cotinine (ng/dL) by

Time and by Farm Type Tobacco Use F (1, 69) P value

Time Tobacco Use

Self Report

7.59 0.008

Tobacco Use

Exhaled CO level

7.44 0.008

Time by Smoking

Tobacco Use

Self Report

2.78 0.10

Tobacco Use

Exhaled CO level

1.08 0.301

Time by Farm Type

Tobacco Use

Self Report

0.68 0.415

Tobacco Use

Exhaled CO level

0.90 0.347

Planting Season (time 1 pre-exposure)

Workers with Possible GTS Farm Type Worker

Tobacco Use

+ Self Report

Tobacco Use

CO > 8Salivary Cotinine (ng/dL)

Tobacco No No 0

Tobacco Yes No 16

Nursery Yes No 194

Nursery No No 0

Nursery Yes No 12

Nursery Yes No 24

Harvest Season (time 2 during exposure)

Workers with Possible GTS Farm Type Worker

Tobacco Use

+ Self Report

Tobacco Use

CO > 8Salivary Cotinine (ng/dL)

Tobacco No No 0

Tobacco Yes No 33

Tobacco Yes Yes 325

Tobacco Yes Yes Missing data

Nursery Yes No 25

Discussion• No statistically significant increase in salivary cotinine between

planting and harvest time among shade tobacco farmworkers • Among all studied farmworkers (nursery and tobacco) there was

a statistically significant increase in cotinine levels over time. This effect remains even when controlling for type of farm. There was a trend indicating that tobacco use may have played a role in this increase.

• During the harvest season, there was no difference between the cotinine levels of the tobacco farmworkers compared to the control group (nursery workers).

• GTS: non-specific case definition– 1 tobacco worker with possible GTS had a salivary cotinine

level of 0 ng/dL– Unexposed nursery workers with no occupational exposure to

nicotine reported GTS symptoms

Conclusions• Case definition should include documentation of increase in

salivary cotinine• When compared to workers that harvest cigarette tobacco,

shade tobacco farmworkers appear not to have significant occupational exposure to nicotine or high prevalence rate of possible GTS– Work practices- less dermal exposure among shade tobacco

(work practices represent potential interventions that could be introduced during the harvesting of cigarette tobacco)

– Small sample size- unable to detect significant effect– Only two time measurements perhaps losing high peak

levels in between the two sampling periods

Future work• Repeat study with a larger sample size• Collect data at more frequent intervals throughout the

planting and harvest season• Collect data until the end of the harvest season• Enhance tobacco use instrument• Intervention study for cigarette tobacco workers

Funding: NEC-NYCAMH, UCHC HCRAC and UCHC GCRCAcknowledgements: to the many volunteers during the data collection

process and to the administrative support of Miriam Muniz and Cheryl Steciak