Vol 74, No 1 (2023)
Letter to the Editor
Published online: 2023-03-24

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Call for the National Boards of Health and the Maritime Administrations to introduce valid screening for type 2 diabetes at the maritime medical examinations

Olaf Chresten Jensen1, Victoria Corman2, Maria Luisa Canals3, David Lucas4, Ilona Denisenko5, Don Eliseo-III Lucero-Prisno6, Helena Estopà Pujol7, Finn Gyntelberg8, Agnes Flores9, Anne-Mette Hedeager Momsen10
Pubmed: 36974495
IMH 2023;74(1):70-71.


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Int Marit Health
3; 74, 1: 7071
Copyright © 202
ISSN 1641-9251
eISSN 2081-3252

Call for the National Boards of Health and the Maritime Administrations to introduce valid screening for type 2 diabetes at the maritime medical examinations

Olaf Chresten Jensen1Victoria Corman2Maria Luisa Canals3David Lucas4Ilona Denisenko5Don Eliseo-III Lucero-Prisno6Helena Estopà Pujol7Finn Gyntelberg8Agnes Flores9Anne-Mette Hedeager Momsen10
1Centre for Maritime Health and Society, Department of Public Health, University of Southern Denmark, Esbjerg, Denmark
2Department of Public Health, University of Southern Denmark, Esbjerg, Denmark
3University of Cadiz FUECA, Sociedad Española de Medicina Marítima (SEMM)/Sanidad Marítima, Tarragona, Spain
4Seafarers’ Health Unit, Brest, France
5ANO DPO Maritime Medicine, Moscow, Russian Federation
6Faculty of Management and Development Studies, University of the Philippines Open University, Los Baños, Laguna, Philippines
7Sanidad Marítima (ISM), Barcelona, Spain
8National Research Centre for Work Environment, Occupational Medicine Clinic, Bispebjerg, Denmark
9Caja Seguro Social, Vacamonte Rep. of Panamá, Panama
10Public Health Institute, Klinisk Socialmedicin og Rehabilitering, Aarhus, DenmarkWorldwide, in 2019 there were approximately 463 million adults (20–79 years) with type 2 diabetes mellitus (T2DM), by 2045 this number will have increased to 700 million adults. In addition, 374 million people have precursors to T2DM, prediabetes.

Dr. Olaf Jensen, MD, PhD, Centre for Maritime Health and Society, Department of Public Health, Southern Danish University, Degnevej 14, 6705 Esbjerg, Denmark, e-mail: ocj@health.sdu.dk

Received: 30.01.2023 Accepted: 20.02.2023

This article is available in open access under Creative Common Attribution-Non-Commercial-No Derivatives 4.0 International (CC BY-NC-ND 4.0) license, allowing to download articles and share them with others as long as they credit the authors and the publisher, but without permission to change them in any way or use them commercially.

For seafarers and fishermen, there is great social inequity in relation to health, with an increased risk of obesity, metabolic syndrome, T2DM, and hypertension. There is therefore a great need for early and accurate diagnosis as part of prevention and retention in work.

Like several other occupational groups (including lorry drivers), seafarers and fishermen must undergo mandatory health examinations every or every second year by maritime doctors who are general practitioners authorized to carry out these examinations. While around 1.5 million seafarers there are millions of fishermen with medical examinations annual or biannual.

It is a major health problem that significant medical errors occur in these studies in the form of underestimation of the prevalence of T2DM with up to 80% false negatives due to the use of the current method with urine sticks. The prediabetes remains unknown, and an important prevention potential is thus not utilised. Ignorance of the prevalence of prediabetes and T2DM is a serious obstacle to establishing relevant prevention [1–3].

The focus on early diagnosis and prevention of T2DM is based on scientific evidence that preliminary stages of T2DM, prediabetes, are reversible and can be normalised with non-pharmacological measures and, moreover, are assessed to be costeffective. The international guidelines for the diagnosis of T2DM should use laboratory analyses for long-term blood glucose (glycated haemoglobin [HbA1c]) or fasting blood glucose [4]. However, this does not happen in several European and other countries as seen in a random selection from several countries of copies of the forms used to report the results of the maritime medical examinations. Almost all of them use urine dipsticks instead of blood tests with long-term blood glucose or fasting blood glucose as recommended by the American Diabetes Association (ADA) [4].

The overall goal, seen from a medical and scientific perspective, is to establish an early and accurate diagnosis of T2DM during the medical examinations as a background for establishing an effective prevention in collaboration with the maritime doctors, the Maritime Authorities, the shipping companies, and other relevant organizations. Probably as the only country, Spain introduced testing of fasting blood glucose for all seafarers many years ago followed up by a HbA1c test where the fasting glucose is abnormal. Initiatives are currently underway to revise the International Labour Organization/International Maritime Organization (ILO/IMO) guidelines for medical examinations in this area.

In conclusion, there is a need for upgrading the routine “fit for duty” medical examinations also for other transport workers including, truck-, taxi- and locomotive drivers, and airline pilots to replace glucose strip test by either HbA1c or fasting blood glucose test (fasting plasma glucose) for diagnosis of T2DM.

This is hereby a call to the National Boards of Health to revise the national guidelines for the medical doctors on using fasting blood glucose or long-term blood glucose at the medical examinations for precise diagnostics of T2DM. Finally, the medical doctors should report all laboratory results with the key variables to the national occupational/maritime health research centres for analysis on the standard Excel file for use in the research and prevention [5].

Conflict of interest: None declared


  1. Jensen OC, Flores A, Corman V, et al. Screening for type 2 diabetes and hypertension in seafarers’ medical examinations. Int Marit Health. 2022; 73(2): 64–72, doi: 10.5603/IMH.2022.0010, indexed in Pubmed: 35781681.
  2. Jensen OC, Flores A, Corman V, et al. Early diagnosis of T2DM using high sensitive tests in the mandatory medical examinations for fishers, seafarers and other transport workers. Prim Care Diabetes. 2022; 16(1): 211–213, doi: 10.1016/j.pcd.2021.12.018, indexed in Pubmed: 34996691.
  3. Jensen OC, Flores A, Corman V, et al. Rethinking the use of urine dipstick for early diagnosis of Type 2 diabetes mellitus. Diabetes Res Clin Pract. 2022; 184: 109222, doi: 10.1016/j.diabres.2022.109222, indexed in Pubmed: 35114298.
  4. American Diabetes Association. https://diabetes.org/diabetes/a1c/diagnosis.
  5. Medical certifications fit-for-duty: Google Drev [Internet]. https://drive.google.com/drive/folders/1f_BtatpVmIReblKd1zxSDOnQh_xc7WTQ (Cited 2023 Jan 24).