Methods and exploratory findings of the first Swiss agricultural health cohort FarmCoSwiss

Study participants

The CONSORT flow chart gives an overview of the study participation (Fig. 1). A total of 2063 individuals were reached through our recruiting strategy. Of those, 1480 individuals were eligible, fully completed the registration form, and were formally invited via postal mail. Of all invited participants, 947 returned the signed ICF and were therefore registered for the study. A total of 59 individuals who signed the ICF did not respond to the questionnaire or subsequent reminder emails and calls, and thus did not participate in the study. Ten registered individuals withdrew participation after enrolment.

A total of 878 participants started to answer the questionnaire, and 866 fully completed it. As only three participants were partners who did not work in agriculture, they were excluded from this analysis. Since the baseline data collection was closed in August 2023, results from three individuals responding at a later stage were also excluded in the present analyses. The total sample size for analysis was therefore 872.

Of these, 159 participants completed the questionnaire on paper. The average duration for completing the online questionnaire was 36.9 min (median of 32.0 min). The actual duration may be somewhat shorter, as participants had the option of saving their responses and resuming the questionnaire at a later time point. All participants who took more than 120 min to complete the questionnaire (n = 123) were excluded from this duration calculation, since it is assumed that they took a long break.

Non-responder

A total of 238 registered individuals indicated their intention to withdraw from the study by completing the short non-responder survey either after receiving the study information or signing the ICF. The non-responder questionnaire in German, French, and Italian can be found in the supplementary data (S7–S9). In short, the non-responder questionnaire consisted of 10 questions about reasons for non-participation, socio-demographic and farm-related characteristics and about the general health and quality of life, measured on a 5-point Likert scale. Table A2 in the appendix gives an overview of the non-responding individuals’ characteristics in comparison to FarmCoSwiss participants. In general, more men and individuals with a somewhat lower educational level and above the age of 65 were non-responders. Descriptively comparing the self-reported general health status in responders and non-responders, non-responders reported potentially poorer health. A multiple choice question was used to determine the reasons for non-participation. The most frequently selected reasons for non-participation were “no time” (46%), “too much effort” (40.1%), and “not interested or convinced of the purpose of the study” (27.8%). Other reasons were “doubts about data protection measures” (19.4%), “I refuse to participate in studies in general” (5.5%), “illness” (3.8%), “I do not fulfill the conditions for participation” (9.3%) or “other” (19.8%).

Sociodemographic characteristics

Table 1 describes basic socio-demographic characteristics of the 872 FarmCoSwiss participants. A total of 579 participants (65.9%) were male and only 33 participants (3.8%) had a low educational level, defined as attending only mandatory primary and secondary school (≤ 9 years). The majority of participants (81.2%) was in the age range of 35–64 years. Figure 2 depicts the geographical regions in Switzerland. Participation rate generally corresponded to region size, with most participants from Espace Mittelland (n = 271) and Eastern Switzerland (n = 217) regions.

Farm characteristics

Farm characteristics are displayed in Table 2. The vast majority of participants (89.7%) reported to work on farms that can be broadly classified as either livestock farming or mixed production, which includes the cultivation of crops in addition to livestock. A detailed overview of the types of animal farming and crop production can be found in the appendix (Figs. A1 and A2). Most farms (77.1%) were between 11 and 50 ha in size. Moreover, 77.4% of participants worked on non-organic farms. Roughly three quarters of participants (75.1%) were (co-)manager of their farm and 67.4% of participants owned the farm. Three quarters (75.2%) of participants worked full-time in agriculture.

To assess representativeness of the FarmCoSwiss study population, Table 3 displays selected variables in comparison to their distribution within the Swiss agricultural population based on data from the Swiss Federal Statistical Office of 2022³¹. The study sample consisted of 34.1% female participants, similar to the 36.7% women in Swiss agriculture in 2023³². The geographical distribution of farms in FarmCoSwiss was similar to the national distribution³³. Organic farms (22.4%) were slightly overrepresented in our sample³⁴. Farms of size < 5 ha made up 3.3% of the FarmCoSwiss sample, but 16.0% of all Swiss farms, and 49.2% of farms in our study were of size 21–50 ha compared to 37.8% with size 20– < 50 ha in Swiss agriculture³⁵.

Health-related quality of life

Mean MCS and PCS of the SF-12v2 were 47.6 (± 10.0) and 51.9 (± 7.6), respectively. With a mean of 53.1 (± 6.5), results suggest a slightly higher PCS in female participants compared to men (51.4, ± 8.0). The opposite trend was observed for the MCS, with a mean of 46.5 (± 10.0) for women and 48.2 (± 10.0) for men.

The distribution of the MCS and PCS according to sex and age is presented in Fig. 3. There was a general trend for increasing mental health and decreasing physical health scores with aging. At younger ages, findings suggest lower average mental health than physical health scores. Around 55–64 years of age, mental health scores exceeded physical health scores in men, whereas in women, this trend was observed at 65–74 years of age. In general, there was an indication for higher physical health, but lower mental health, scores in women compared to men.

Lifestyle and BMI

Table 4 displays the distribution of the lifestyle variables sitting time, physical activity, diet, smoking status, alcohol consumption, and BMI, stratified by age and sex. On average, participants reported to sit more hours per day on a rest-day than on a day of work. Similarly, findings suggest that physical activity was on average higher across all sex- and age-groups on a work day compared to a rest day.

An examination of dietary patterns across all age groups indicates that, on average, individuals consumed raw vegetables more frequently than fruit, meat, or cooked vegetables. Men under the age of 50 reported the highest consumption frequency of meat, with an average of 5.0 days per week, while women aged 50 and above reported the lowest consumption frequency, with an average of 4.1 days per week.

A majority of participants in each age and sex group stated to have never smoked. The rate of never smokers was similar between men younger than 50 years (54.4%) and men in the older age group (62.0%), but was reportedly higher in women ≥ 50 years (83.9%) than in younger women (68.8%). The highest share of current smokers was found in men under 50 (29.3%).

Regarding alcohol consumption, most study participants reported to drink less than once a week (58.4%). While 36.7% of men under 50 years reported to consume alcohol several times a week, the share in the same age group for women was 16.8%. A similar pattern was found for participants of age 50 and older.

Concerning BMI, the majority of participants were classified as overweight or obese (60.5%). In all age and sex groups, obesity rates were around 15%. Men under and above 50 years of age had overweight rates of 49.3% and 54.8%, respectively. With 24.3% for women under 50 years old and 37.9% for women of 50 years and older, overweight rates were reportedly lower in female participants.

Stress and sleep quality

Table 5 describes participants’ self-reported stress level and sleep quality for both the cold and warm season. For both age and sex groups, comparative results suggest lower mean scores for perceived stress level in the cold season compared to the warm season. Stress levels were suggestively higher in women compared to men. A greater share of all participants reported very good sleep quality during the cold season compared to the warm season. Generally, most participants reported good or very good sleep quality in both seasons. However, women ≥ 50 years old more often stated to have mediocre or bad sleep quality in both seasons (cold: 43.6%, warm: 49.2%).

Comparisons to Swiss general population samples

For a better interpretation of the baseline findings, the study population was compared to two Swiss general population samples: first, to data from the SHS 2022 for lifestyle-related variables and second, to the fifth follow-up of the SAPALDIA cohort (2020–2023) for disease lifetime prevalences. Figure 4 in chapter 3.8.1 gives an overview of the selected lifestyle variables (sitting time, meat consumption, smoking status, alcohol consumption, and BMI) descriptively compared with the general Swiss population (SHS).Tables 6 and 7 in chapter 3.8.2 present prevalences of self-reported diseases and accidents in the FarmCoSwiss and SAPALDIA cohorts.

Lifestyle variables

Roughly 50% of FarmCoSwiss participants stated to sit for less than 4 h a day. In the SHS, this proportion was only about 30% (Fig. 4). Furthermore, the proportion of FarmCoSwiss participants who reported sitting for 10 h or more a day was comparatively lower than in the SHS across all age categories and for both men and women. While comparative findings indicated a slight trend toward more hours spent sitting with older age in the FarmCoSwiss cohort, SHS data suggested the opposite trend in the general population.

While most FarmCoSwiss participants reported to eat meat 4 to 6 days a week (women: 53.6%, men: 57.2%), the percentage was comparatively lower in the SHS, with 30.0% of female and 40.9% of male participants (Fig. 4). Women less frequently stated to consume meat daily as compared to men, both in the farmers’ cohort (women: 12.9%, men: 18.3%) and the SHS (women: 7.4%, men: 15.8%). Findings further suggest lower meat consumption in older individuals in both studies.

FarmCoSwiss participants generally reported lower smoking rates compared to the SHS population (Fig. 4). While SHS data indicated slightly decreasing smoking rates with age, FarmCoSwiss participants between 55 and 64 reported the lowest smoking rates (12.6%). In both studies, the rate of current smokers was lower in women than in men (FarmCoSwiss women: 12.5%, men: 21.2%; SHS women: 20.8%, men: 27.1%).

Comparative results further indicated less frequent alcohol consumption in the FarmCoSwiss cohort as compared to the SHS. In almost all age groups, most FarmCoSwiss participants stated to drink alcohol less than once a week (Fig. 4). Only in the age group 65–74, more participants (38.1%) reported alcohol consumption several times a week or daily. In contrast, nearly 50% in most age groups of SHS stated to drink alcohol several times a week. Daily alcohol consumption was less frequent in women than in men, in both FarmCoSwiss (women: 0.0%, men: 4.6%) and SHS (women: 4.9%, men 12.4%).

While the self-reported prevalences of overweight and obesity increased with age in both FarmCoSwiss and SHS, there was a trend toward higher overweight and obesity rates in the FarmCoSwiss sample compared to the SHS (Fig. 4). In both studies, overweight prevalence was reportedly higher in men than in women (FarmCoSwiss women: 30.4%, men: 52.7%; SHS women: 22.8%, men: 39.1%).

Lifetime prevalences of self-reported diseases and accidents

For FarmCoSwiss participants aged ≥ 50 years, lifetime prevalences of 11 pre-selected diseases were descriptively compared to lifetime prevalences from the fifth SAPALDIA follow-up as shown in Table 6. Lifetime prevalence of occupational and non-occupational accidents in the FarmCoSwiss cohort was compared to the 1-year prevalence of accidents reported in the SHS (Table 7). All prevalences were stratified by sex.

In both cohorts, highest prevalences were reported for osteoarthritis (FarmCoSwiss: 41.7%, SAPALDIA: 43.2%), chronic back pain (FarmCoSwiss: 22.8%, SAPALDIA: 30.6%), cardiovascular diseases (FarmCoSwiss: 11.9%, SAPALDIA: 26.1%), and allergies (FarmCoSwiss: 16.3%, SAPALDIA: 46.6%). Prevalences of all diseases were higher in the SAPALDIA population than in the FarmCoSwiss population, with the exception of osteoarthritis in men (FarmCoSwiss: 43.0%, SAPALDIA: 38.6%) and COPD (FarmCoSwiss: 3.9%, SAPALDIA: 2.1%). Female FarmCoSwiss participants reported higher prevalences for allergies (men: 11.5%, women: 28.2%), depression or anxiety disorder (men: 8.9%, women: 17.7%), cancer (men: 6.2%, women: 9.7%), asthma (men: 4.9%, women: 9.7%), and diabetes (men: 2.3%, women: 4.0%). In SAPALDIA, women had higher prevalences of osteoarthritis (men: 38.6%, women: 48.1%), chronic back pain (men: 29.9%, women: 31.3%), allergies (men: 43.1%, women: 50.3%), depression or anxiety disorder (men: 14.0%, women: 22.0%), and asthma (men: 11.8%, women: 13.8%). Differences in disease prevalences between men and women for chronic back pain, allergies, cancer, asthma, COPD, stroke, and diabetes were generally larger in the FarmCoSwiss sample than in the SAPALDIA population.

The rate of occupational accidents was reportedly higher in the FarmCoSwiss cohort than in the SHS, and higher in men than in women (FarmCoSwiss men: 47.1%, women: 28.3%; SHS men: 7.8%, women: 3.7%). Non-occupational accidents were most prevalent among men in the general Swiss population (19.1%).