Why were Sardinians the shortest Europeans? A journey through genes, infections, nutrition, and sex

Diet and longevity in the Blue Zones: A set-and-forget issue?

The Blue Zones (BZs) are areas of the globe inhabited by exceptionally long-lived populations. They include the island of Okinawa in Japan, the island of Ikaria in Greece, the mountain area of the island of Sardinia in Italy, and the peninsula of Nicoya in Costa Rica. Their longevity is a relatively recent phenomenon that has been progressively investigated since the dawn of this century. Research efforts over the past two decades have sought to shed light on the factors associated with this longevity, as well as explore the possibility of lessons transferable to the general population. Among the features of BZ inhabitants, described in the literature, their eating habits hold a prominent place, as these have the advantage of being easily quantifiable and applicable on a larger scale. However, it is too often taken for granted that the mere fact of being documented in a long-lived population makes the diet a causal factor of that population's longevity; this is a claim which should be proven. Furthermore, it is implicitly assumed that a specific BZ diet is homogeneous and remains stable over time, whereas some evidence suggests the opposite. Therefore, this review summarizes our current knowledge of the BZ diets and discusses whether they can be considered as a paradigmatic example of healthy nutrition valid for anyone or, rather, a set of evolving food patterns that has offered benefits to a few specific communities in recent decades.

Short Stature: Understanding the Stature of Ethnicity in Height Determination

Height is a polygenic trait with a high degree of heritability. Most (95%) children with short stature (defined as height below the third percentile) and poor growth (growth velocity <5 cm/year) do not have an endocrine disorder. The genetic basis for stature potential has been evaluated in recent years and is increasingly being recognized as a major basis for variation in height between different ethnic populations. Numerous genome-wide association studies have identified hundreds of loci linked to human growth. Apart from the genetic factors, various environmental, nutritional, hormonal, and socioeconomic factors also influence the height, and stature of individuals varies between different geographical locations and ethnic groups. Ethnically different populations might respond differently to the same environmental factors and thus the final height in different ethnic groups is different. This review covers in detail the short stature of African Pygmies and Andamanese Islanders along with the possible causative factors responsible for the variation in height in these ethnic groups.

Spatial Association between Gastric Cancer Mortality and Goiter in Sardinia

Background:

Gastric cancer (GC) is the third leading cause of cancer mortality worldwide. The incidence of GC varies between countries according to exposure to different risk factors. Hypothyroidism has been suggested as a potential GC risk factor. In Sardinia, Italy, the prevalence of endemic goiter is high and GC mortality is unevenly distributed. This ecological study aimed to investigate GC mortality and its relationship with hypothyroidism, adjusting for potential confounders.

Methods:

The spatial association between GC mortality and goiter (a proxy of hypothyroidism), diet, stature and pastoralism (a proxy of Helicobacter pylori infection), available at the aggregated level, was modelled in the island’s 377 municipalities, separately by sex, using geographically weighted regression (GWR).

Results:

The GC standardized mortality ratio ranged from 0.0 to 10.4 across municipalities. A hotspot of GC mortality was detected in the central mountainous area of Sardinia among males, positively associated with goiter (GWR estimate 0.213 ± 0.122), and the practice of sheep‒rearing (GWR estimate 0.127 ± 0.080), whereas a negative association with the diet score (GWR estimate 0.032 ± 0.034), and null for stature were found. No significant associations were found in females.

Conclusion:

Within the limitations of ecological studies goiter prevalence was an independent predictor of GC mortality in males.

Dietary Habits, Anthropometric Features and Daily Performance in Two Independent Long-Lived Populations from Nicoya peninsula (Costa Rica) and Ogliastra (Sardinia)

(1) Background: Longevity Blue Zones (LBZs) are populations characterized by exceptional longevity. The purpose of this cross-sectional study was to compare the food habits of two representative samples of the oldest old subjects from the population residing in the LBZs of Nicoya peninsula (Costa Rica) and in the mountainous part of Ogliastra (Sardinia, Italy). (2) Methods: Data were collected using validated tools, including a food frequency questionnaire, Basic Activities of Daily Living (BADL) and Instrumental Activities of Daily Living (IADL) scales for functional autonomy, body mass index, and waist and limbs circumferences. (3) Results: A total of 210 subjects, 60 (31 male) from Nicoya (age range 80–109 years), and 150 (61 male) from Ogliastra (age 90–101 years) were included in the study. In both populations, the highest frequencies of consumption were recorded for plant-derived foods (cereals 60–80% daily, legumes ≥ 80% daily in Nicoya, ≥ 60% 2–5 servings/week in Ogliastra), followed by those of animal origin (dairy products, meat) ≥60% and 80% daily, in Nicoya and Ogliastra, respectively. The frequency of milk consumption showed a positive correlation with BADL (ρ = 0.268 for Nicoya and ρ = 0.214 for Ogliastra) and IADL scores (ρ = 0.466 for Nicoya and ρ = 0.471 for Ogliastra), whereas legumes consumption correlated negatively with self-rated health (ρ = −0.264) and IADL (ρ = −0.332). (4) Conclusions: Our results indicate that the dominant dietary model among the elderly of Nicoya and Ogliastra is a plant-based diet complemented by a non-negligible consumption of animal products, mostly dairy products. Further prospective studies are needed to ascertain a possible cause–effect relationship between food habits and increased likelihood of reaching advanced age.

The association of adult height with the risk of cardiovascular disease and cancer in the population of Sardinia

The relationship between body height and the risk of non‒communicable diseases such as cardiovascular disease and cancer has been the subject of much debate in the epidemiological literature. Concerns have recently arisen over spurious associations due to confounding factors like birth cohort, especially in the context of epidemiological transition. The population of Sardinia represents an interesting case study, as the average physical stature of inhabitants was the lowest recorded in Europe until a few decades ago. In this population we tested whether height is an independent risk factor for cardiovascular disease and cancer. We analysed the stature of 10,427 patients undergoing endoscopy for any reason, for whom a detailed clinical history of cardiovascular disease and/or malignancies had been documented. Poisson regression modelling was used to test the association between stature and disease risk. When patients were subdivided according to sex and height tertiles, the risk of cardiovascular disease proved significantly greater for subjects in the lowest tertile irrespective of sex (men: 1.87; 95%CI 1.41‒2.47; women: 1.23; 95%CI 0.92‒1.66) and smaller for those in the highest tertile (men: 0.51; 95%CI 0.35‒0.75; women: 0.41; 95%CI 0.27‒0.61). However, after adjusting the risk for birth cohort and established risk factors, it mostly resulted in non-significant values, although the overall trend persisted. Similar results were obtained for all-cancer risk (relative risk for men and women in the lowest tertile: 1.44; 95%CI 1.09–1.90 and 1.17; 95%CI 0.93–1.48, in the highest tertile: 0.51; 95%CI 0.36–0.72 and 0.62; 95%CI 0.47–0.81, respectively) as well as for some of the most common types of cancer. We concluded that the risk of developing cardiovascular disease and malignancies does not vary significantly with stature in the Sardinian population, after adjusting for birth cohort and more obvious risk factors.