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. Author manuscript; available in PMC: 2020 Jul 1.
Published in final edited form as: Mutat Res. 2019 Feb 10;781:186–206. doi: 10.1016/j.mrrev.2019.02.001

Table 8:

Key differences between AHS 2005 and AHS 2018, with an emphasis on exposure quantification

AHS 2005 [19] AHS 2018 [24]
Exposure assessment Self-report at baseline Self-report at baseline and follow-up questionnaire with exposure simulation1
Exposure quantification Ever/never Cumulative exposure days Intensity-weighted exposure days2 Ever/never3 Cumulative exposure days3 Intensity-weighted exposure days2
Lag period Unlagged Unlagged 5-year lag 20-year lag4
Exposure groups among exposed (days)5 Ever exposed T1: 1-20;
T2: 21-56;
T3: 57-2678		 T1: 0.1-79.5;
T2: 79.6-337.1;
T3: 337.2-18,241		 Ever exposed T1: 1-19.9;
T2: 20.0-61.9;
T3: >62.0		 Q1: 1–598.9;
Q2: 599–1649.9;
Q3: 1650–4339.9;
Q4: >4340.0		 Q1: 1–530.9;
Q2: 531.0–1511.9;
Q3: 1512.0–4063.4;
Q4: >4063.5		 Q1: 1–281.3;
Q2: 281.4–895.9;
Q3: 896–2609.9;
Q4: >2610.0
Exposure duration (years)6 Maximum possible range= 20-24;7
Actual maximum: 7.38
Median = not provided;
IQR = not provided 		Maximum possible range = 26–32;9
Actual maximum: not provided
Median = 8.5;
IQR = 5-14		 Max. possible range = 21-27;9
Actual max: not provided
Median = 4.1 ;10
IQR = not provided 		Max. possible range = 6-12;9
Actual max: not provided
Median = 2.5;10
IQR = not provided
Reference group Unexposed Lowest exposure tertile Lowest exposure tertile Unexposed
Potential Exposure misclassification Differential misclassification unlikely;
Non-differential misclassification likely		 Differential misclassification possible;
Non-differential misclassification likely
Follow-up (years) Median = 6.7;
Maximum possible = 911 		Median = not provided
Maximum possible = 2011
Outcome inclusion Multiple myeloma (MM) not included in NHL cases Multiple myeloma (MM) included in NHL cases
1

This was referred to as “multiple imputation” by study authors; see manuscript text for further details

2

The algorithm for calculating “intensity-weighted exposure days” was updated between 2005 and 2018. Key differences include rescaling of scores by a factor of 10 and altering the weights for mixing, certain pesticide application techniques, and the use of chemically resistant gloves [44]. Therefore, these metrics cannot be directly compared.

3

Ever/never and cumulative exposure days were only presented in the AHS 2018 supplement but are presented here to facilitate comparisons with AHS 2005

4

Results and quartiles for 10- and 15-year lags are presented in the AHS 2018 supplement

5

Exposure group abbreviations are as follows: Tertiles = “T;” Quartiles = “Q.”

6

The values provided in this row are based on the subset of individuals who reported using glyphosate

7

This theoretical maximum duration value was calculated based on the year that glyphosate entered the market (1974) and the end of AHS enrollment (1993-1997), since AHS 2005 used only baseline exposure information

8

This value was calculated based on the upper bound of the cumulative exposure days tertiles

9

These theoretical maximum duration values were calculated based on the year that glyphosate entered the market (1974) and the end of AHS follow-up exposure questionnaire (1999-2005), with the appropriate adjustments for the lag times as indicated.

10

These medians were calculated using the information provided in the footnote in Table 3 of the AHS 2018 publication

11

These follow-up times were calculated based on timing of study enrollment and follow-up