Background: Sigmoid volvulus (SV) is a colonic obstruction form, in which sigmoid colon wraps around itself. The aim of this study is to evaluate the role of dietary and defecation habits in the development of SV.
Materials and methods: The records of the largest single-centre SV series over the world including 1,036 patients treated over a 54.5-year period between June 1966 and January 2021, were reviewed.
Results: Of the patients, 589 (56.9%) had a high-fiber and vegetable diet habit, while 326 (31.5%) had chronic constipation. There was a significant decrease in the incidence of SV in the latter 27.5-year period when compared with that of the first 27 years (cases per year from 25.6 to 12.3 and cases per 100,000 persons per year from 9.2 to 2.2, p<0.001, for each).
Conclusion: Some dietary and defecation habits including chronic constipation and high-fibre diet may be responsible for SV and the decrease in the incidence of SV may be due to the westernization of dietary habits.

As more engineering projects and activities are taking place on and around weak rocks, it is becoming more important to study and characterize them. Since regular practices of rock mechanical testing are not effective for weak rocks, special laboratory tests and measurements were performed to characterize the Alkharj Saudi weak sandstone rock which is a clastic rock dominantly sandy limestone and sandstone. Test results are presented in this paper. Porosity, permeability, and mechanical properties (stress, strain, Poisson\'s ratio, confined compressive strength (CCS) and unconfined compressive strength (UCS)) were obtained, then used to characterize the proposed weak rock. This paper provides a mean of classifying weak soft rocks despite encountered problems in handling and testing such materials.