The study, published in PLOS Mental Health, drew on enrollment data collected between March 2019 and August 2021 from adults aged 18 and older living in urban Haiti. Participants completed the Patient Health Questionnaire-9, a widely validated nine-item screening instrument that scores depressive symptoms on a scale from zero to 27. The researchers dichotomized the scores, treating values below 10 as none to mild and values of 10 or above as moderate to severe, a cutoff commonly used in clinical and epidemiological research to flag depression that warrants treatment. Cardiovascular outcomes were not self-reported in a casual sense; instead, cases of angina, myocardial infarction, transient ischemic attack, stroke, and heart failure were adjudicated using epidemiologic definitions aligned with international cohort studies, lending the prevalence estimates a rigor that is often difficult to achieve in settings without routine diagnostic infrastructure.

The scale of psychological distress documented in the cohort was striking. Among the 2,995 participants, who had a mean age of 41.9 years and were 58 percent female, 16.2 percent reported moderate to severe depressive symptoms. That overall figure, however, concealed a sharp gender divide: 22 percent of women screened in the moderate-to-severe range compared with just 8.5 percent of men. This nearly threefold difference in symptom burden echoes patterns seen globally, where women consistently report higher rates of depression, but it takes on particular significance in Haiti, where economic instability, food insecurity, and the aftermath of repeated disasters weigh heavily on household life.

When the researchers cross-tabulated depressive symptoms with adjudicated cardiovascular disease, the association emerged clearly in both sexes. Among men with moderate to severe symptoms, 21.5 percent had prevalent cardiovascular disease, compared with 10.6 percent of men with none to mild symptoms. Among women, the corresponding figures were 23.3 percent versus 15.3 percent. In other words, cardiovascular disease was roughly twice as common among the most symptomatic men and about half again as common among the most symptomatic women, a pattern that persisted across the cohort’s urban neighborhoods.

To move beyond raw prevalence differences, the team employed generalized estimating equation Poisson models with a log link, a statistical approach well suited to estimating prevalence ratios in cross-sectional data where odds ratios can overstate effect sizes for common outcomes. The models adjusted for an unusually comprehensive set of covariates: age, sex, education, income, food insecurity, smoking, alcohol use, physical activity, stress, and body mass index. This adjustment strategy matters enormously in a Haitian context, where food insecurity and material hardship are widespread and could otherwise masquerade as a depression–cardiovascular link. Even after these adjustments, moderate to severe depressive symptoms remained independently associated with a 36 percent higher prevalence of cardiovascular disease, with an adjusted prevalence ratio of 1.36 and a 95 percent confidence interval of 1.08 to 1.71.

Sex-stratified analyses revealed a consistent but nuanced picture. Among women, the adjusted prevalence ratio was 1.38 with a confidence interval of 1.06 to 1.78, indicating a statistically robust association. Among men, the point estimate was somewhat lower at 1.25, but the confidence interval of 0.75 to 1.99 crossed the null, reflecting the smaller number of men in the cohort and the lower prevalence of depressive symptoms among them. The researchers also examined effect modification on the additive scale using the relative excess risk due to interaction, a measure that captures whether the combined burden of being female and depressed exceeds what would be expected from adding the two risks together. The RERI estimate of 0.07, with a confidence interval spanning −0.74 to 0.88, provided limited evidence for additive interaction, and formal tests of multiplicative modification were likewise not statistically significant.

These null interaction findings should not be mistaken for evidence that sex is irrelevant. The point estimates for women were consistently stronger, and the authors describe a stronger pattern among women even while acknowledging that formal significance thresholds were not met. In epidemiological terms, the study was likely underpowered to detect interaction, particularly given the modest number of men with moderate to severe symptoms. The practical takeaway is that depression and cardiovascular disease travel together in both sexes in urban Haiti, with a suggestive but unproven intensification among women that future, larger studies will need to confirm.

The findings carry weight because they emerge from a setting where cardiovascular disease has overtaken infectious disease as the dominant killer, yet mental health remains chronically under-resourced. Haiti has only a handful of psychiatrists for a population of more than eleven million, and depression screening is rarely integrated into routine care, let alone into cardiovascular prevention programs. The study’s authors argue that integrating depression screening into cardiovascular disease prevention could help address the growing dual burden of both conditions in resource-limited settings. Such integration need not be technologically sophisticated; the Patient Health Questionnaire-9 is short, free to administer, and already validated in numerous languages and cultural contexts, making it a realistic addition to community health worker visits and hypertension clinics alike.

Mechanistically, the depression–cardiovascular connection is thought to run along several converging pathways. Depression is associated with dysregulation of the hypothalamic-pituitary-adrenal axis and elevated cortisol, heightened systemic inflammation, impaired endothelial function, and increased platelet aggregability, all of which promote atherosclerosis and thrombosis. Behavioral channels compound these biological ones: people with depression are more likely to smoke, drink heavily, remain physically inactive, and adhere poorly to medications, while also eating less healthful diets. In Haiti, where the cohort’s own adjustment variables reveal how tightly food insecurity, stress, and poverty are woven into daily life, disentangling these pathways is an empirical challenge that cross-sectional data cannot fully resolve. The authors are explicit on this point, calling for prospective studies to clarify the underlying mechanisms and causal pathways.

What the study establishes is a robust cross-sectional association in a population that has been almost entirely absent from the global cardiovascular literature. Most of what medicine knows about the depression–heart disease link comes from high-income countries, where patients have access to lipid panels, electrocardiograms, and cardiologists. The Haiti Cardiovascular Disease Cohort demonstrates that the same epidemiological tools—validated symptom scales, adjudicated outcome definitions, and carefully adjusted prevalence models—can be deployed in one of the world’s most constrained health systems and yield findings of genuine global relevance. If depression screening becomes a routine part of cardiovascular prevention in Port-au-Prince and cities like it, the payoff could extend beyond Haiti: roughly three-quarters of cardiovascular deaths worldwide occur in low- and middle-income countries, and this study suggests that a treatable mental health condition may be quietly amplifying that toll.

Subject of Research: The association between depressive symptoms and prevalent cardiovascular disease in urban Haiti

Article Title: Depressive symptoms and association with prevalent cardiovascular disease: A cross-sectional analysis in Port-au-Prince, Haiti

Article References: Pierre, D. M., Rasul, R., St. Sauveur, R., Celestin, K., Rouzier, V., Hilaire, E., Deschamps, M. M., Pape, J. W., Yan, L. D., Ogyu, A., Bennett, C., McNairy, M. L., Sufra, R., & Nash, D. (2026). Depressive symptoms and association with prevalent cardiovascular disease: A cross-sectional analysis in Port-au-Prince, Haiti. PLOS Mental Health, 3(8), e0000693. https://doi.org/10.1371/journal.pmen.0000693

Image Credits: AI Generated

DOI: 10.1371/journal.pmen.0000693

Keywords: depression, cardiovascular disease, Haiti, Port-au-Prince, PHQ-9, cross-sectional study, sex differences, global health, mental health, low- and middle-income countries, epidemiology, comorbidity

The research team, led by Renesky Jean Mary of the Federal University of Latin American Integration in Brazil together with colleagues at the University of São Paulo and the Federal University of Amapá, framed the city not as a set of isolated flood zones but as a single connected hydrogeomorphic system. Water that falls on the high southern uplands near Kenscoff, where elevations climb to roughly 2,159 metres, does not stay there. It moves rapidly through dissected ridges, steep slopes, and confined valleys via rivers such as the Grise and the Froide and the Bois-de-Chêne ravine, arriving within minutes or hours at the low-relief coastal plain occupied by Port-au-Prince, Delmas, Cité Soleil, and Tabarre. Hydrogeological work has already shown that infiltration from these rivers is a principal source of recharge for the Cul-de-Sac alluvial aquifer, confirming that the mountain block and the lowlands function as one hydrological unit.

To capture that connectivity, the researchers used a technique called geomorphon classification, applied to a 30-metre digital elevation model with the r.geomorphon module in GRASS GIS. The algorithm compares terrain visibility in multiple directions and assigns every cell to a local landform class such as ridge, slope, valley, base of slope, or plain. Unlike a simple slope map, this approach distinguishes terrain units associated with runoff generation, transfer, and accumulation. The result is a functional picture of the landscape: ridges and slopes in the south generate runoff, valleys act as transfer corridors, and the flat coastal plain receives and concentrates the flow. When vegetation is stripped from ridges and slopes and replaced with impervious surfaces, the volume and speed of water delivered to the lowlands can increase even if the converted cells themselves are never classified as high-risk terrain.

The land-cover mapping behind the study was unusually rigorous. Landsat 8 classifications for 2015, 2020, and 2025 achieved overall accuracies of 98.44, 95.92, and 94.13 percent, with Kappa coefficients of 0.9704, 0.9362, and 0.9069 respectively. Rather than reporting raw pixel counts, the team applied the area-adjustment method of Olofsson and colleagues, using error matrices to produce corrected class areas with nominal 95 percent confidence intervals. The adjusted built-up estimate rose from 80.79 square kilometres in 2015 to 226.92 square kilometres in 2020, a gain equivalent to 180.9 percent of the starting value, and then to 335.43 square kilometres in 2025, an increase of 315.2 percent over the decade. Vegetation fell from an adjusted 458.08 square kilometres to 277.17 square kilometres, and the remaining green cover became increasingly fragmented along the transition between the coastal plain and the southern uplands.

One of the study’s most technically interesting results concerns the choice of satellite sensor. For 2025, the team produced a parallel classification from Sentinel-2 at 10-metre resolution, which achieved 99.35 percent overall accuracy and a Kappa of 0.9908. Yet the two sensors disagreed dramatically on class shares: Landsat 8 allocated 42.6 percent of the area to built-up land, while Sentinel-2 allocated only 17.9 percent, a ratio of 2.38. The authors are careful to explain that this is not sensor bias but a consequence of spatial support. A single 30-metre Landsat pixel in a dense informal settlement typically mixes rooftops, roads, bare soil, and sparse vegetation, and the whole pixel gets assigned to one class, often built-up. The finer Sentinel-2 grid resolves that sub-pixel structure, separating exposed soil, which received 34.7 percent under Sentinel-2 versus 18.7 percent under Landsat 8, from genuinely impervious surfaces. For planners deciding where drainage investments should go, that distinction matters enormously.

Combining the 2025 Sentinel-2 land cover, slope, and flow accumulation into a weighted flood-susceptibility index, with weights of 40, 25, and 35 percent respectively, the study found that moderate and high susceptibility concentrates overwhelmingly in Tabarre, Delmas, and Cité Soleil. These communes occupy low-relief coastal and alluvial surfaces where modeled flow convergence, extensive urban sealing, and restricted drainage coincide. High susceptibility is not spread evenly but follows drainage axes and geographically confined depressions. Gressier, Kenscoff, and Carrefour show predominantly low susceptibility at the commune scale because of their steeper upland terrain, yet moderate and high classes persist locally along valley bottoms and downslope outlets, a reminder that commune averages can hide sharply confined hazards. An overlay of historical flood and rainfall disaster records from humanitarian and local sources showed broad spatial agreement with the susceptibility map, with the largest documented event counts in Cité Soleil and Port-au-Prince, though the authors stress this comparison is a qualitative plausibility check rather than statistical validation, since official georeferenced disaster records in Haiti remain fragmented.

The precipitation analysis added a troubling temporal dimension. Drawing on five daily gridded products for 1983 to 2024, including CHIRPS, ERA5, ERA5-Land, AgERA5, and PERSIANN-CDR, the team computed standard climate extremes indices and tested trends with the two-sided Mann-Kendall test, complemented by Benjamini-Hochberg and Benjamini-Yekutieli corrections for the many repeated cellwise tests. The most consistent signal across products was an increase in consecutive dry days, the longest run of days with less than one millimetre of rain. During the December-to-February season, the median statistically significant area reached 81.5 percent and was fully retained after false-discovery adjustment, with the strongest drying trends, exceeding 0.40 days per year, in northeastern and eastern cells. Annual total precipitation on wet days showed predominantly negative but non-significant slopes, indicating no uniform wetting or drying tendency.

At the same time, the frequency of very heavy rainfall events showed geographically restricted increases. During June to August, the count of days exceeding 60 and 80 millimetres rose significantly across large portions of the arrondissement, with a median significant area of 70.5 percent that survived Benjamini-Hochberg adjustment almost intact at 69.1 percent. Positive tendencies also appeared in August one-day maximum rainfall and precipitation above the 99th percentile, though little or no significant area remained after conservative multiplicity control. The authors interpret this combination, longer dry spells alongside occasional intense downpours, as greater rainfall irregularity acting on a landscape whose runoff pathways and vulnerable receiving areas are already established. They explicitly caution that the analysis does not show dry spells causing subsequent flooding, and that the absence of a continuous quality-controlled local rain-gauge record prevents direct validation of the gridded products.

Interpreted through the Pressure and Release framework, the study treats urban expansion and vegetation loss as dynamic pressures, occupation of steep terrain and flood-prone plains as unsafe conditions, and intense rainfall as the immediate trigger. That framing keeps the physical susceptibility analysis separate from social vulnerability while allowing both to inform the same risk picture, an important distinction in a city where access to drainage, secure housing, and protective infrastructure is deeply unequal. The authors recommend prioritizing drainage rehabilitation and maintenance in Tabarre, Delmas, Cité Soleil, and coastal Port-au-Prince, protecting and restoring vegetation on ridges, steep slopes, valley margins, and river corridors, using Sentinel-2-class imagery for current planning while retaining Landsat for long-term monitoring, and expanding rain-gauge coverage and georeferenced disaster inventories. The susceptibility map, they emphasize, is a screening tool for field investigation and community-informed planning, not a calibrated prediction of inundation depth. What the evidence supports, cautiously but clearly, is that a decade of breakneck construction across hydrologically connected terrain has raised the potential for rapid runoff delivery toward the densely occupied lowlands, and that greater rainfall irregularity may magnify the consequences of that transformation for millions of residents.

Subject of Research: Urban expansion, flood susceptibility, and precipitation extremes across the mountain-to-coastal gradient of the Port-au-Prince Arrondissement, Haiti

Article Title: Urban expansion across a mountain-to-coastal gradient and its implications for hydrogeomorphic risk in Port-au-Prince, Haiti

Article References: Mary, R. J., de Bodas Terassi, P. M., da Silva Scheer, M. A. P., Palhares, J. M., & Rauber, A. L. (2026). Urban expansion across a mountain-to-coastal gradient and its implications for hydrogeomorphic risk in Port-au-Prince, Haiti. Natural Hazards, 122(18), Article 622. https://doi.org/10.1007/s11069-026-08384-3

Image Credits: AI Generated

DOI: 10.1007/s11069-026-08384-3

Keywords: Port-au-Prince, Haiti, urban expansion, flood susceptibility, land-use change, remote sensing, Landsat 8, Sentinel-2, geomorphons, precipitation extremes, hydrogeomorphic risk, runoff connectivity