Study of Chronic Exposure of the Population Living on the Atlantic Coast and on the Caribbean Coast, in Martinique, During the Stranding Period and Outside the Stranding Period of Sargassum Seaweeds

Summary

Sargassum are pelagic brown sea algae. Two species grow on the surface of the ocean and drift freely with ocean currents in the form of slicks: the pelagic Sargassum fluitans and Sargassum natans.

Since 2011, massive strandings of Sargassum seaweed in the French West Indies are to be deplored. In recent years, strandings have increased. In Martinique, sargassum stranding occurs mainly on the Atlantic coast. The duration of stranding from one year to another is variable, but the period during which the stranding is maximum is between April and October.

The accumulation of strandings causes the compaction of algae and limits access to oxygen, which leads to anaerobic degradation which quickly results in the release of various gases, in particular hydrogen sulphide (H2S).

Acute H2S poisoning is well characterized clinically according to exposure (cutaneous, respiratory, ophthalmological, digestive, neurological symptoms, etc.). On the other hand, there are very few data available on the clinical effects of prolonged, repeated exposure and most often at low doses.

Among the toxic effects for which there are still uncertainties regarding long-term exposure to H2S are lung function, measured by spirometry, and airway inflammation, appreciable by measurement of FeNO (fractional exhaled nitric oxide).

The investigators consider it relevant to focus on the clinical and biological characteristics of the population exposed to sargassum in Martinique, in the field, assuming that exposure to sargassum H2S causes pulmonary effects measurable by spirometry and by FeNO, during the stranding period and outside this period.

Conditions

• Obstructive Ventilatory Disorders

Interventions

PROCEDURE

FeNO (fractional exhaled nitric oxide)

FeNO measurement is a marker of airway inflammation. It is a non-invasive examination for the patient, easy to perform for healthcare personnel, the measurement of NO in exhaled air is one of the only non-invasive and reproducible examinations allowing the detection of inflammation airways. The FeNO will be measured by an electrochemical NO analyzer of the NiOx Vero type (Circassia, The Surgical Company) and expressed in particles per billion (ppb). The objective and reproducible measurement of NO production by the bronchial mucosa is a reflection of the degree of airway inflammation. The measurement of exhaled NO is part of diagnostic health technologies aimed at quantifying airway inflammation, especially in asthmatic patients. FeNO is considered normal for values of 16-25 ppb. A FeNO value \> 25 ppb will be a reason for consultation at the Martinique Hospital for additional assessment.

PROCEDURE

Spirometry

Spirometry tests will assess lung function. It is a safe and painless test to measure lung volumes and expiratory flows. Ventilatory function is assessed by simple spirometry parameters such as forced expiratory volume in the first second (FEV1, in litres), vital capacity (CV, in litres), and the FEV1/CV ratio. The results of the spirometry will be compared with the theoretical or predicted values calculated according to age, sex, height.The FEV1/CV ratio as a percentage is an indicator of the level of bronchial obstruction. Spirometry is considered normal for CV values ≥80% and FEV1/FVC ≥0.70 of the predicted value. A value of CV \<80% or FEV \<80% of the predicted value will be a reason for consultation at the Martinique hospital for additional assessment.

OTHER

Physical examination

A pulmonary clinical examination will be carried out by the investigator, including: * Cough, * Sputum, * Vesicular murmur (MV), * Added noises (BSA), * Vocal vibrations (VV), * Tympanism, * Dullness, * Signs of acute respiratory distress (ARD), * …

OTHER

Interrogation

Participants will undergo an interview with the medical team to collect the following information in particular: Age, size, sex, medical history, smoking status, current treatments, potential symptoms, date of first symptoms, clinical manifestations experienced (respiratory, digestive, neurological, cardiac, psychiatric, visual, skin disorders, etc.) place of residence, concentration H2S in ppm on the site, presence of sand mist in the environment, etc.

Sponsors & Collaborators

• University Hospital Center of Martinique

  lead OTHER

Study Design

Allocation

NON_RANDOMIZED

Purpose

DIAGNOSTIC

Masking

NONE

Model

PARALLEL

Eligibility

Min Age

18 Years

Sex

ALL

Healthy Volunteers

Yes

Timeline & Regulatory

Start

2022-08-18

Primary Completion

2023-03-28

Completion

2023-03-28

Countries

• France