Fertility and malaria in Sardinia

Area of Science:

• Demographic studies
• Epidemiology
• Human genetics

Background:

• Malaria was endemic in Sardinia during the study period.
• Fertility patterns can be influenced by environmental and genetic factors.
• Sardinia presents a unique demographic and genetic landscape.

Purpose of the Study:

• To investigate the relationship between malaria endemicity and fertility rates in Sardinia.
• To explore the role of cultural and social factors on fertility.
• To examine the potential genetic basis for differential fertility in malaria-endemic regions.

Main Methods:

• Analysis of 1961 Italian census data for Sardinian women.
• Classification of areas based on malaria intensity (Fermi's classification).
• Comparison of heterozygote frequencies for thalassaemia and G-6-PD deficiency.

Main Results:

• Differential fertility observed between women in low and high malaria-rate areas.
• Education level and urban character negatively correlated with fertility.
• Higher fitness suggested for women in high-malaria areas, potentially linked to genetic factors.
• Significant differences in heterozygote frequencies found between areas, with village-level variability.

Conclusions:

• Malaria intensity, genetic factors (thalassaemia, G-6-PD deficiency heterozygosity), and immunity may explain higher fitness in high-malaria regions.
• Cultural and social factors also significantly impact fertility rates.
• Ecological changes may have altered historical malaria distribution and its genetic consequences.