Controlling hypertension at sea

Kristin Urdahl, Gard Senior Loss Prevention Executive, Arendal has noted that hypertension, or high blood pressure, can lead to stroke, heart and kidney disease and other serious medical conditions. While a healthy diet, exercise and appropriate medication can reduce high blood pressure, detection of elevated blood pressure was an essential first step in treatment of a condition that is a recurring cause of crew illness.

Despite being straightforward to diagnose and relatively easy to treat with low-cost medicines, hypertension now affected more than 1bn adults aged 30-79 globally, according to a WHO funded study. It is one of the top causes of death and disease throughout the world.

The study identified that nearly half of the people with hypertension were unaware of their condition, and close to 60% with the condition were not receiving the treatment that they needed. The study also saw that the percentage of people who have hypertension in the world has changed very little over the past 30 years. However, the occurrence of hypertension has shifted in balance from wealthy nations to low and middle-income countries.

Gard noted that hypertension was a recurring cause of crew illness claims, with approximately 3% of all crew illness claims reported to it each year. If one takes into account the fact that hypertension can also be an underlying cause of other illnesses, such as heart disease and stroke, the condition was likely to be responsible for a considerably larger share of our illness claims.

Many people with hypertension do not notice symptoms and may be unaware there is a problem. When symptoms do occur, they can include headache, nosebleeds, shortness of breath, dizziness, chest pain, irregular heartbeat, and general fatigue.

Detecting hypertension can be achieved quickly by the use of a cuff on the upper arm. Hypertension is diagnosed if, when it is measured on two different days, the systolic blood pressure readings on both days is ≥140 mmHg and/or the diastolic blood pressure readings on both days is ≥90 mmHg.

If left untreated, hypertension can cause persistent chest pain (angina), heart attacks, heart failure, and an irregular heartbeat. Hypertension can also cause strokes by blocking or bursting arteries that supply blood and oxygen to the brain, as well as kidney damage, which can lead to kidney failure.

Gard said that its claims data were not sufficiently detailed to make any firm conclusions about the prevalence of hypertension among seafarers, a study of Danish seafarers published in 2016 found that the prevalence of hypertension among the 629 seafarers studied was more than three times the prevalence in the general Danish population at the time. The study further observed that:

  • In all age-groups, the prevalence of hypertension was higher in seafarers than in the applied control group of Danes, including among younger seafarers.
  • The prevalence of hypertension increased with rising Body Mass Index (BMI).
  • There was slightly less hypertension in non-smokers than in former and current smokers, and seafarers with the highest alcohol consumption also had the highest prevalence of hypertension.
  • Seafarers working in the engine room, the noisiest area of a ship, had the highest prevalence of hypertension across all workplaces onboard.
  • The majority of the hypertensive seafarers in the study did not receive antihypertensive medication. In fact, compared to hypertensive seafarers, seven times as many hypertensive persons in the control group of Danes were in treatment.

The Danish study population was predominantly male, with a high number of overweight seafarers among those studied. However, the study concluded that its findings could be generalized and a high rate of hypertension was also likely to exist among seafarers in a global context who shared similar maritime exposures and lifestyles as the Danish seafarers.

The additional risks for seafarers were not hard to list:

  • demanding working conditions and high levels of stress, particularly when vessels are in port,
  • shiftwork, as well as occasional long hours of work,
  • limited opportunities for leisure activities, and
  • restricted food choices.

In addition, Gard noted that the social isolation and loneliness associated with being away from family and friends for very long periods could be linked to higher risks for a variety of physical and mental conditions, which might be associated with subsequent onset of hypertension.

Furthermore, the Danish study referred to above also suggests a potential causal relationship between noise levels and hypertension.

Gard accepted that the evidence to support this might be somewhat uncertain, but many research studies on chronic exposure to road traffic and/or railway or aircraft noise do indicate an increased risk of hypertension related to long-term noise exposure.

Gard said that, while ships could never duplicate home life, “ship operators should do their utmost to facilitate a healthy lifestyle onboard their ships”. A healthy lifestyle is considered the first line of defence against hypertension and the common recommendations provided by the WHO, health authorities, and health care providers focus on:

  • reducing salt intake (to less than 5gm daily),
  • eating more fruit and vegetables,
  • being physically active on a regular basis,
  • avoiding the use of tobacco,
  • reducing alcohol consumption,
  • limiting the intake of foods high in saturated fats, and
  • eliminating/reducing trans fats in the diet.

Gard accepted that to make sustainable lifestyle changes would not be easy. For those working at sea for weeks and months at a time, where the jobs were often physically and mentally demanding, involved watches and shifts and broken sleep patterns, it could seem like a virtually impossible task. “Effectively dealing with chronic diseases such as hypertension in the maritime environment therefore requires a comprehensive and holistic approach to crew health and wellbeing. Implementation of lifestyle measures, for example, requires knowledge, enthusiasm, patience, considerable time spent with seafarers, and reinforcement”.