Published May 26, 2026 | Version v1
Acyclic Directed Mixed Graph Open

Causal relationship between nights shifts and depressive symptoms

Contributors

  • 1 Utrecht University

Visualisation

Description

The directed acyclic graph (DAG) represents the hypothesized relationships between night shift work and depression, including potential confounding and mediating variables. Night shifts were considered the main exposure and depression the outcome of interest. Sociodemographic and lifestyle-related factors, including age, sex, education, marital status, smoking, alcohol consumption, BMI, physical activity, chronotype, sleep quality, and study center, were included as covariates based on their potential influence on both the exposure and the outcome. The DAG also includes interrelationships among these variables, reflecting plausible causal pathways identified in the literature.

According to the DAG, the minimal sufficient adjustment set for statistical models contained age, center, chronotype, education, marital status, and sex for estimating the total effect of night shift work on depressive symptoms. The fully adjusted models also accounted for the potential mediating variables smoking and physical activity. Alcohol consumption, sleep quality, and BMI were considered collider variables based on the DAG structure and were therefore not included in the statistical adjustment models.

Variables

13 nodes
  • Night Shifts Exposure No description
  • Depression Outcome No description
  • Marital status No description
  • Physical activity No description
  • Sleep quality No description
  • Age No description
  • Alcohol No description
  • BMI No description
  • Center No description
  • Chronotype No description
  • Education No description
  • Sex No description
  • Smoking No description

Relationships

62 edges

List Matrix
  • Marital status Night Shifts
  • Marital status Physical activity
  • Marital status Alcohol
  • Marital status BMI
  • Marital status Depression
  • Marital status Smoking
  • Night Shifts Physical activity
  • Night Shifts Sleep quality
  • Night Shifts Alcohol
  • Night Shifts BMI
  • Night Shifts Depression
  • Night Shifts Smoking
  • Physical activity Sleep quality
  • Physical activity Depression
  • Physical activity BMI
  • Sleep quality Alcohol
  • Age Marital status
  • Age Night Shifts
  • Age Physical activity
  • Age Sleep quality
  • Age Alcohol
  • Age Chronotype
  • Age Depression
  • Age Education
  • Age Smoking
  • Alcohol BMI
  • Alcohol Depression
  • Alcohol Smoking
  • BMI Sleep quality
  • BMI Depression
  • Center Marital status
  • Center Physical activity
  • Center Alcohol
  • Center BMI
  • Center Depression
  • Center Education
  • Center Smoking
  • Chronotype Night Shifts
  • Chronotype Physical activity
  • Chronotype Sleep quality
  • Chronotype Alcohol
  • Chronotype BMI
  • Chronotype Depression
  • Chronotype Smoking
  • Depression Sleep quality
  • Depression Smoking
  • Education Marital status
  • Education Night Shifts
  • Education Physical activity
  • Education BMI
  • Education Depression
  • Sex Night Shifts
  • Sex Physical activity
  • Sex Sleep quality
  • Sex Alcohol
  • Sex Chronotype
  • Sex Depression
  • Sex Education
  • Sex Smoking
  • Smoking Physical activity
  • Smoking Sleep quality
  • Smoking BMI

Read across: each marked cell is an edge from the row's variable to the column's.

  • No sign given
  • Directed
  • Bidirected
Night ShiftsDepressionMarital statusPhysical activitySleep qualityAgeAlcoholBMICenterChronotypeEducationSexSmoking
Night Shifts
Depression
Marital status
Physical activity
Sleep quality
Age
Alcohol
BMI
Center
Chronotype
Education
Sex
Smoking

Code

Submitted as opencausal_tbvvzwhj.txt. Also available as:

JSON CSV DAGitty

This JSON follows CausalJSON 0.2, the Open Causal Graph Format.

{
  "$schema": "https://opencausal.org/causaljson/0.2/causaljson.schema.json",
  "graph": {
    "id": "tbvvzwhj",
    "version": 1,
    "title": "Causal relationship between nights shifts and depressive symptoms",
    "description": "The directed acyclic graph (DAG) represents the hypothesized relationships between night shift work and depression, including potential confounding and mediating variables. Night shifts were considered the main exposure and depression the outcome of interest. Sociodemographic and lifestyle-related factors, including age, sex, education, marital status, smoking, alcohol consumption, BMI, physical activity, chronotype, sleep quality, and study center, were included as covariates based on their potential influence on both the exposure and the outcome. The DAG also includes interrelationships among these variables, reflecting plausible causal pathways identified in the literature. \r\n\r\nAccording to the DAG, the minimal sufficient adjustment set for statistical models contained age, center, chronotype, education, marital status, and sex for estimating the total effect of night shift work on depressive symptoms. The fully adjusted models also accounted for the potential mediating variables smoking and physical activity. Alcohol consumption, sleep quality, and BMI were considered collider variables based on the DAG structure and were therefore not included in the statistical adjustment models.",
    "type": "admg",
    "created": "2026-05-26T10:56:22+00:00",
    "authors": [
      {
        "given_name": "Melpomeni",
        "family_name": "Bazaka",
        "orcid": "0009-0005-4396-877X",
        "affiliations": [
          {
            "name": "Utrecht University"
          }
        ]
      }
    ],
    "submitter": {
      "given_name": "Melpomeni",
      "family_name": "Bazaka",
      "orcid": "0009-0005-4396-877X"
    },
    "license": "CC-BY-4.0",
    "rights_url": "https://creativecommons.org/licenses/by/4.0/legalcode",
    "publisher": "Open Causal",
    "language": "en",
    "layout": {
      "coordinate_system": "screen"
    }
  },
  "nodes": [
    {
      "id": "Marital_status",
      "label": "Marital status",
      "position": {
        "x": 1.041,
        "y": -0.905
      }
    },
    {
      "id": "Night_Shifts",
      "label": "Night Shifts",
      "role": "exposure",
      "position": {
        "x": -2.107,
        "y": 0.064
      }
    },
    {
      "id": "Physical_activity",
      "label": "Physical activity",
      "position": {
        "x": 0.373,
        "y": 1.627
      }
    },
    {
      "id": "Sleep_quality",
      "label": "Sleep quality",
      "position": {
        "x": -0.424,
        "y": 1.828
      }
    },
    {
      "id": "Age",
      "label": "Age",
      "position": {
        "x": 0.651,
        "y": -1.738
      }
    },
    {
      "id": "Alcohol",
      "label": "Alcohol",
      "position": {
        "x": -1.178,
        "y": 1.64
      }
    },
    {
      "id": "BMI",
      "label": "BMI",
      "position": {
        "x": 0.962,
        "y": 1.178
      }
    },
    {
      "id": "Center",
      "label": "Center",
      "position": {
        "x": -0.034,
        "y": -2.147
      }
    },
    {
      "id": "Chronotype",
      "label": "Chronotype",
      "position": {
        "x": -0.857,
        "y": -2.114
      }
    },
    {
      "id": "Depression",
      "label": "Depression",
      "role": "outcome",
      "position": {
        "x": 1.295,
        "y": 0.109
      }
    },
    {
      "id": "Education",
      "label": "Education",
      "position": {
        "x": -1.864,
        "y": -0.923
      }
    },
    {
      "id": "Sex",
      "label": "Sex",
      "position": {
        "x": -1.442,
        "y": -1.799
      }
    },
    {
      "id": "Smoking",
      "label": "Smoking",
      "position": {
        "x": -1.824,
        "y": 1.239
      }
    }
  ],
  "edges": [
    {
      "source": "Marital_status",
      "target": "Night_Shifts",
      "type": "directed"
    },
    {
      "source": "Marital_status",
      "target": "Physical_activity",
      "type": "directed"
    },
    {
      "source": "Marital_status",
      "target": "Alcohol",
      "type": "directed"
    },
    {
      "source": "Marital_status",
      "target": "BMI",
      "type": "directed"
    },
    {
      "source": "Marital_status",
      "target": "Depression",
      "type": "directed"
    },
    {
      "source": "Marital_status",
      "target": "Smoking",
      "type": "directed"
    },
    {
      "source": "Night_Shifts",
      "target": "Physical_activity",
      "type": "directed"
    },
    {
      "source": "Night_Shifts",
      "target": "Sleep_quality",
      "type": "directed"
    },
    {
      "source": "Night_Shifts",
      "target": "Alcohol",
      "type": "directed"
    },
    {
      "source": "Night_Shifts",
      "target": "BMI",
      "type": "directed"
    },
    {
      "source": "Night_Shifts",
      "target": "Depression",
      "type": "directed"
    },
    {
      "source": "Night_Shifts",
      "target": "Smoking",
      "type": "directed"
    },
    {
      "source": "Physical_activity",
      "target": "Sleep_quality",
      "type": "directed"
    },
    {
      "source": "Physical_activity",
      "target": "Depression",
      "type": "directed"
    },
    {
      "source": "Physical_activity",
      "target": "BMI",
      "type": "bidirected"
    },
    {
      "source": "Sleep_quality",
      "target": "Alcohol",
      "type": "bidirected"
    },
    {
      "source": "Age",
      "target": "Marital_status",
      "type": "directed"
    },
    {
      "source": "Age",
      "target": "Night_Shifts",
      "type": "directed"
    },
    {
      "source": "Age",
      "target": "Physical_activity",
      "type": "directed"
    },
    {
      "source": "Age",
      "target": "Sleep_quality",
      "type": "directed"
    },
    {
      "source": "Age",
      "target": "Alcohol",
      "type": "directed"
    },
    {
      "source": "Age",
      "target": "Chronotype",
      "type": "directed"
    },
    {
      "source": "Age",
      "target": "Depression",
      "type": "directed"
    },
    {
      "source": "Age",
      "target": "Education",
      "type": "directed"
    },
    {
      "source": "Age",
      "target": "Smoking",
      "type": "directed"
    },
    {
      "source": "Alcohol",
      "target": "BMI",
      "type": "directed"
    },
    {
      "source": "Alcohol",
      "target": "Depression",
      "type": "bidirected"
    },
    {
      "source": "Alcohol",
      "target": "Smoking",
      "type": "bidirected"
    },
    {
      "source": "BMI",
      "target": "Sleep_quality",
      "type": "directed"
    },
    {
      "source": "BMI",
      "target": "Depression",
      "type": "bidirected"
    },
    {
      "source": "Center",
      "target": "Marital_status",
      "type": "directed"
    },
    {
      "source": "Center",
      "target": "Physical_activity",
      "type": "directed"
    },
    {
      "source": "Center",
      "target": "Alcohol",
      "type": "directed"
    },
    {
      "source": "Center",
      "target": "BMI",
      "type": "directed"
    },
    {
      "source": "Center",
      "target": "Depression",
      "type": "directed"
    },
    {
      "source": "Center",
      "target": "Education",
      "type": "directed"
    },
    {
      "source": "Center",
      "target": "Smoking",
      "type": "directed"
    },
    {
      "source": "Chronotype",
      "target": "Night_Shifts",
      "type": "directed"
    },
    {
      "source": "Chronotype",
      "target": "Physical_activity",
      "type": "directed"
    },
    {
      "source": "Chronotype",
      "target": "Sleep_quality",
      "type": "directed"
    },
    {
      "source": "Chronotype",
      "target": "Alcohol",
      "type": "directed"
    },
    {
      "source": "Chronotype",
      "target": "BMI",
      "type": "directed"
    },
    {
      "source": "Chronotype",
      "target": "Depression",
      "type": "directed"
    },
    {
      "source": "Chronotype",
      "target": "Smoking",
      "type": "directed"
    },
    {
      "source": "Depression",
      "target": "Sleep_quality",
      "type": "directed"
    },
    {
      "source": "Depression",
      "target": "Smoking",
      "type": "bidirected"
    },
    {
      "source": "Education",
      "target": "Marital_status",
      "type": "directed"
    },
    {
      "source": "Education",
      "target": "Night_Shifts",
      "type": "directed"
    },
    {
      "source": "Education",
      "target": "Physical_activity",
      "type": "directed"
    },
    {
      "source": "Education",
      "target": "BMI",
      "type": "directed"
    },
    {
      "source": "Education",
      "target": "Depression",
      "type": "directed"
    },
    {
      "source": "Sex",
      "target": "Night_Shifts",
      "type": "directed"
    },
    {
      "source": "Sex",
      "target": "Physical_activity",
      "type": "directed"
    },
    {
      "source": "Sex",
      "target": "Sleep_quality",
      "type": "directed"
    },
    {
      "source": "Sex",
      "target": "Alcohol",
      "type": "directed"
    },
    {
      "source": "Sex",
      "target": "Chronotype",
      "type": "directed"
    },
    {
      "source": "Sex",
      "target": "Depression",
      "type": "directed"
    },
    {
      "source": "Sex",
      "target": "Education",
      "type": "directed"
    },
    {
      "source": "Sex",
      "target": "Smoking",
      "type": "directed"
    },
    {
      "source": "Smoking",
      "target": "Physical_activity",
      "type": "directed"
    },
    {
      "source": "Smoking",
      "target": "Sleep_quality",
      "type": "directed"
    },
    {
      "source": "Smoking",
      "target": "BMI",
      "type": "directed"
    }
  ]
}
source,target,edge_type
Marital_status,Night_Shifts,directed
Marital_status,Physical_activity,directed
Marital_status,Alcohol,directed
Marital_status,BMI,directed
Marital_status,Depression,directed
Marital_status,Smoking,directed
Night_Shifts,Physical_activity,directed
Night_Shifts,Sleep_quality,directed
Night_Shifts,Alcohol,directed
Night_Shifts,BMI,directed
Night_Shifts,Depression,directed
Night_Shifts,Smoking,directed
Physical_activity,Sleep_quality,directed
Physical_activity,Depression,directed
Physical_activity,BMI,bidirected
Sleep_quality,Alcohol,bidirected
Age,Marital_status,directed
Age,Night_Shifts,directed
Age,Physical_activity,directed
Age,Sleep_quality,directed
Age,Alcohol,directed
Age,Chronotype,directed
Age,Depression,directed
Age,Education,directed
Age,Smoking,directed
Alcohol,BMI,directed
Alcohol,Depression,bidirected
Alcohol,Smoking,bidirected
BMI,Sleep_quality,directed
BMI,Depression,bidirected
Center,Marital_status,directed
Center,Physical_activity,directed
Center,Alcohol,directed
Center,BMI,directed
Center,Depression,directed
Center,Education,directed
Center,Smoking,directed
Chronotype,Night_Shifts,directed
Chronotype,Physical_activity,directed
Chronotype,Sleep_quality,directed
Chronotype,Alcohol,directed
Chronotype,BMI,directed
Chronotype,Depression,directed
Chronotype,Smoking,directed
Depression,Sleep_quality,directed
Depression,Smoking,bidirected
Education,Marital_status,directed
Education,Night_Shifts,directed
Education,Physical_activity,directed
Education,BMI,directed
Education,Depression,directed
Sex,Night_Shifts,directed
Sex,Physical_activity,directed
Sex,Sleep_quality,directed
Sex,Alcohol,directed
Sex,Chronotype,directed
Sex,Depression,directed
Sex,Education,directed
Sex,Smoking,directed
Smoking,Physical_activity,directed
Smoking,Sleep_quality,directed
Smoking,BMI,directed

dag {
Marital_status [label="Marital status",pos="1.041,-0.905"]
Night_Shifts [exposure,label="Night Shifts",pos="-2.107,0.064"]
Physical_activity [label="Physical activity",pos="0.373,1.627"]
Sleep_quality [label="Sleep quality",pos="-0.424,1.828"]
Age [pos="0.651,-1.738"]
Alcohol [pos="-1.178,1.64"]
BMI [pos="0.962,1.178"]
Center [pos="-0.034,-2.147"]
Chronotype [pos="-0.857,-2.114"]
Depression [outcome,pos="1.295,0.109"]
Education [pos="-1.864,-0.923"]
Sex [pos="-1.442,-1.799"]
Smoking [pos="-1.824,1.239"]
Marital_status -> Night_Shifts
Marital_status -> Physical_activity
Marital_status -> Alcohol
Marital_status -> BMI
Marital_status -> Depression
Marital_status -> Smoking
Night_Shifts -> Physical_activity
Night_Shifts -> Sleep_quality
Night_Shifts -> Alcohol
Night_Shifts -> BMI
Night_Shifts -> Depression
Night_Shifts -> Smoking
Physical_activity -> Sleep_quality
Physical_activity -> Depression
Physical_activity <-> BMI
Sleep_quality <-> Alcohol
Age -> Marital_status
Age -> Night_Shifts
Age -> Physical_activity
Age -> Sleep_quality
Age -> Alcohol
Age -> Chronotype
Age -> Depression
Age -> Education
Age -> Smoking
Alcohol -> BMI
Alcohol <-> Depression
Alcohol <-> Smoking
BMI -> Sleep_quality
BMI <-> Depression
Center -> Marital_status
Center -> Physical_activity
Center -> Alcohol
Center -> BMI
Center -> Depression
Center -> Education
Center -> Smoking
Chronotype -> Night_Shifts
Chronotype -> Physical_activity
Chronotype -> Sleep_quality
Chronotype -> Alcohol
Chronotype -> BMI
Chronotype -> Depression
Chronotype -> Smoking
Depression -> Sleep_quality
Depression <-> Smoking
Education -> Marital_status
Education -> Night_Shifts
Education -> Physical_activity
Education -> BMI
Education -> Depression
Sex -> Night_Shifts
Sex -> Physical_activity
Sex -> Sleep_quality
Sex -> Alcohol
Sex -> Chronotype
Sex -> Depression
Sex -> Education
Sex -> Smoking
Smoking -> Physical_activity
Smoking -> Sleep_quality
Smoking -> BMI
}

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